Conditions · Face · Scars

Acne Scars: Icepick, Boxcar or Rolling?

Medically reviewed by Dr Sin Yong · Last reviewed · 12 min read · Assessed personally by Dr Sin Yong · Jump to questions

“Acne scars” is a category, not a diagnosis. The classification physicians use — icepick, boxcar, rolling, plus raised hypertrophic scars — exists because each shape reflects a different injury below the surface and answers to a different tool. Most scarred faces carry a mixture, which is why one-device treatment plans disappoint.

WhatsApp Dr Sin Yong →
Invited by Device Makers to Share His Expertise
International KOL for 14+ device brandsShared his clinical expertise with 500+ doctors across AsiaMBBS (NUS) · MRCS (Edinburgh) · MSc with Distinction (Queen Mary, London) · MSc (Cardiff)Every assessment personally by Dr Sin Yong

Rolling acne scar treatment depends on scar type: icepick, boxcar and rolling scars each reflect a different injury below the surface. Rolling scars are broad undulations tethered by fibrous bands, so they are released rather than resurfaced. Most faces carry a mixture, which is why mapping the scars comes before choosing any device.

Also called: pitted scars, pockmarks, 痘疤, 痘坑, ニキビ跡

In brief
  • Acne scars are classed as icepick, boxcar and rolling atrophic scars, and each reflects a different injury beneath the surface.
  • Rolling scars are broad undulations tethered by fibrous bands, so they are released rather than resurfaced.
  • Most faces carry a mixture, so the scars are mapped before any device or injectable is chosen.
Key takeaways
  • Acne scars are classed as icepick, boxcar and rolling atrophic scars, and each reflects a different injury beneath the surface.
  • Rolling scars are broad undulations tethered by fibrous bands, so they are released rather than resurfaced.
  • Most faces carry a mixture, so the scars are mapped before any device or injectable is chosen.
  • Scar treatment is staged and usually begins once active acne is under control.
  • Improvement is the honest endpoint; no approach returns skin to an unmarked state.
On this page
  1. Key Facts
  2. Why the shape of a scar decides its treatment
  3. Matching tool to scar
  4. The two rules that protect your money
  5. What doesn't work
  6. Which type do you have?
  7. What does not work, and why
  8. When to see a doctor
  9. Myths we hear in clinic
  10. Questions Patients Actually Ask
  11. Dr Sin Yong explains
  12. Rolling acne scars: what they are and how they are treated
  13. Boxcar vs ice pick scars: how to tell them apart

Key Facts

The standard classification
Icepick, boxcar and rolling atrophic scars — the system proposed by Jacob et al. and still in clinical use
Icepick
Narrow (<2 mm), deep, V-shaped tracts — often deeper than any resurfacing laser reaches
Boxcar
Wider, sharp-walled, flat-bottomed depressions — the resurfacing responders
Rolling
Broad undulations tethered from below by fibrous bands — released, not resurfaced
The mixed rule
Most patients carry two or three types on one face; mapping precedes treatment
Timing rule
Scar treatment begins after acne control — treating scars under active acne is building on a battlefield
Close-up of uneven skin texture with raised and depressed areas
Assessment comes before any device or injectable is chosen.
Acne scar types in cross-sectionFour skin cross-sections showing ice pick, boxcar, rolling and hypertrophic scars, each with the approach usually considered: TCA CROSS, fractional resurfacing or RF microneedling, subcision, steroid injection or silicone.Four acne scar shapes and how each is usually approachedIce picknarrow, deep,V-shaped pitusually approached byTCA CROSSBoxcarwider, sharp edges,flat baseusually approached byFractionalresurfacing orRF microneedlingRollingtetherbroad and soft,tethered belowusually approached bySubcisionHypertrophicraised above theskin surfaceusually approached bySteroid injectionor siliconeMost faces carry a mix; the scar shape, not the brand of device, decides the sequence.
Ice pick, boxcar, rolling and hypertrophic scars in cross-section, with the approach each is usually assessed for.

Not sure which scar type you have? Try the four-question checker →

Why the shape of a scar decides its treatment

The classification literature — from Jacob's original system to its modern updates — is built on one clinical fact: scar morphology encodes the injury beneath [1,2]. An icepick scar is a deep epithelial tract punched by a ruptured follicle; a boxcar is a block of lost dermis with intact edges; a rolling scar is skin of near-normal quality yanked downward by fibrous tethers to deeper tissue. Same disease, three different structural problems — and a treatment brilliant for one is irrelevant for another. Resurface an icepick and you polish the rim of a well. Subcise a boxcar and nothing changes, because nothing was tethered.

“If someone offers you one treatment for your acne scars, they haven't looked closely enough.”

Dr Sin YongOn mixed acne scars · from his Instagram explainer series
A young woman with calm, even skin in profile against a plain background
Active acne is treated before scars are addressed.

Matching tool to scar

The evidence-based management literature maps the toolkit [2,3]: icepick scars respond to focal chemical reconstruction (TCA CROSS) and punch techniques; boxcars to fractional ablative resurfacing; rolling scars to subcision that releases the tethers, often with fillers or biostimulation supporting the released skin; hypertrophic and keloid scars — a different biology entirely — to the injection-based pathway on the keloid page. Energy-based collagen remodelling — fractional CO2, RF microneedling — runs across types as the field-improvement layer. This is why Dr Sin Yong's Tetra Pro SCAR3 programme and 4D scar reconstruction begin with a mapped scar census, not a device booking — the plan is a sequence assembled per face. Flat dark marks are a different problem: see PIH.

The two rules that protect your money

First: control the acne before reconstructing its damage — active disease keeps manufacturing new scars behind every repair, so the acne programme comes first when lesions are still appearing. Second: expect a campaign, not an event. The literature is consistent that meaningful atrophic scar revision is staged — collagen remodelling matures over months between sessions — and that improvement, not erasure, is the honest endpoint [2,3]. Anyone promising scar removal in one session is describing neither the evidence nor the biology.

What doesn't work

Scar creams and oils on established atrophic scars — a structural deficit does not refill from the surface. Aggressive scrubbing or home dermarollers — uncontrolled micro-injury on scar-prone skin risks new damage, including PIH in Asian skin. One-device-fixes-all packages — a face carrying icepick, boxcar and rolling scars needs a sequenced mix, and a clinic that offers only one modality will treat every scar as if it were the type their machine handles. And waiting for scars to fade — atrophic scars persist without intervention; time softens edges, not deficits.

“A treatment brilliant for one scar type is irrelevant for another — resurfacing an icepick scar just gives the well a polished rim.”

— Dr Sin Yong
Acne scar treatment plan: decision guideFlowchart: active acne is controlled first; otherwise the dominant scar type routes to TCA CROSS, fractional resurfacing or RF microneedling, subcision then resurfacing, or steroid injection or silicone, with mixed patterns sequenced.Acne scars: how the treatment plan is routedAcne scarring concernIs the acne still active?yesControl the acne first;scar work waits for the skin to settlenoWhich scar type dominates?(most faces carry a mix)Assessed in stretched skin andangled light, scar by scar.ice pickTCA CROSSboxcarFractionalresurfacing orRF microneedlingrollingSubcision first,then resurfacingraised / keloidSteroid injectionor siliconeMixed pattern: sequenced as release, support, then resurfaceRoutes name the assessment, not an outcome. The order and number of sessions are decided at review.
Active acne is controlled first; the dominant scar type then routes to TCA CROSS, resurfacing or RF microneedling, subcision, or steroid injection.

Which type do you have?

Acne scar types and look-alikes, and how each is approached
Type / look-alikeHow to recognise itWhat it needsWhat does not work
Icepick scar (narrow pitted type)Narrow, deep, pit-like mark that barely changes when skin is stretchedFocal chemical reconstruction or punch techniques, decided on examinationSurface resurfacing alone, which only polishes the rim
Boxcar scar (wider flat-based type)Wider depression with sharp walls and a flat baseFractional ablative resurfacing, planned for pigment-prone skinCreams and subcision, since nothing is tethered
Rolling scar (broad wave-like type)Broad, wave-like undulation that flattens when the skin is stretchedSubcision to release tethers, sometimes with filler or biostimulationResurfacing alone, because the tether keeps pulling the skin down
Raised hypertrophic or keloid scar (look-alike)Firm, raised scar that rises above the surrounding skinAn injection-based pathway assessed separatelyTreating it as an atrophic scar with resurfacing
Flat dark mark (post-inflammatory pigment, look-alike)Flat brown or red mark with no depression in the skinAssessment of pigment type, sun protection and pigment-directed careScar procedures aimed at depressions

What does not work, and why

When to see a doctor

Myths we hear in clinic

“One laser or device can treat every type of acne scar.”

Icepick, boxcar and rolling scars reflect different injuries, so a treatment suited to one can be irrelevant to another.

“Scars will fade by themselves if you leave them alone.”

Atrophic scars persist without intervention; time softens edges but does not refill the structural deficit.

Questions Patients Actually Ask

How do I know which scar types I have?+

Stretch test and light: pull the skin taut — rolling scars flatten, boxcars soften slightly, icepicks barely change. Overhead light exaggerates rolling scars. A clinical mapping confirms and counts them.

Can acne scars be completely removed?+

No modality erases scars to unmarked skin — the honest, evidence-based endpoint is substantial, staged improvement. Distrust the word 'removal' in scar marketing.

What is subcision?+

A needle-based release of the fibrous bands tethering rolling scars — freeing the skin so it can sit level again. It targets the mechanism, which is why it beats surface treatment for that type.

Is laser safe for acne scars in darker skin?+

Yes, with fractional settings chosen for pigment-prone skin and strict aftercare — post-treatment pigmentation is the known risk, managed by conservative parameters and photoprotection.

Should I treat scars while still breaking out?+

Control first, reconstruct second. Active acne keeps creating new scars behind each repair — sequencing protects both the result and the spend.

Why do my scars look worse in some lighting?+

Side and overhead light casts shadows into depressions — rolling scars especially. That is also the honest way to photograph progress: same light, same angle, every time.

What causes acne scars?+
Acne scars form when inflammation damages the skin's structure as lesions heal. An icepick scar is a deep tract from a ruptured follicle, a boxcar is a block of lost dermis and a rolling scar is skin tethered downward by fibrous bands. Picking, delayed treatment and deep cyclical lesions increase the risk.
Can acne scars be fully removed?+
No approach returns scarred skin to an unmarked state, and anyone promising complete removal in one visit is not describing the biology. Improvement is the honest endpoint, and it is usually staged, with collagen remodelling maturing between visits. What is realistic depends on scar type, depth, skin tone and whether acne is still active.
Which treatment suits acne scars?+
It depends on the scar type, and most faces carry more than one. Icepick scars, boxcar scars and rolling scars each call for a different tool, and raised scars follow a separate pathway. Decision factors include whether acne is controlled, skin tone and pigment risk, and how deep the scars are. Mapping the scars comes first.
How much does acne scar treatment cost in Singapore?+
The fee depends on the scar types present, the area and number of scars, the tools chosen (such as subcision, resurfacing or biostimulation), whether treatment is staged and whether acne is still being treated. A written quote is given at consultation after the scars are mapped, and the consultation decides whether treatment is advised yet.

References

  1. Acne Scarring: A Classification System and Review of Treatment Options — Journal of the American Academy of Dermatology (PubMed).
  2. A Review and Update of Treatment Options Using the Acne Scar Classification System — Dermatologic Surgery (PubMed).
  3. Evidence-Based Management of Cutaneous Scarring in Dermatology Part 2: Atrophic Acne Scarring — Archives of Dermatological Research (PubMed).

Browse all conditions Dr Sin Yong assesses, or start with a WhatsApp enquiry.

Patient guide (PDF): Acne scar types and options — a printable summary of this page, medically reviewed by Dr Sin Yong. General information, not a substitute for assessment.

Medically reviewed by Dr Sin Yong, MBBS (NUS), MRCS (Edinburgh) · Last updated 7 October 2026 · Editorial policy

Watch

Dr Sin Yong explains

A 30-second stretch test that tells you something real about your scar type. A short video from Dr Sin Yong’s Instagram, with captions.

Watch on Instagram: A 30-second stretch test that tells you something real about your scar type.

Rolling acne scars: what they are and how they are treated

Rolling scars are broad, shallow depressions with soft, sloping edges, caused by fibrous bands that tether the skin to the tissue beneath, so treatment starts by releasing those bands, usually with subcision. They give the cheek an undulating, wave-like surface that shows most in overhead or side light and softens when the skin is stretched, which is the quickest way to tell them from boxcar scars.

Because the skin surface of a rolling scar is close to normal, resurfacing alone treats the wrong layer: the tether keeps pulling the skin down. In subcision, a needle or cannula is passed beneath the scar to cut the bands. Filler or a biostimulator may then be placed to support the released skin and reduce the chance of it re-tethering, and energy-based collagen remodelling such as fractional CO2 or RF microneedling is added later to refine the surface. Some scars need release more than once, and the number of treatments is not fixed in advance. Dr Sin Yong's 4D Scar Reconstruction brings subcision, TCA CROSS, ablative resurfacing and injectable support into one sequenced programme when rolling scars sit alongside other types.

Boxcar vs ice pick scars: how to tell them apart

Boxcar scars are wider, round or oval depressions with sharp vertical edges and a flat base, while ice pick scars are narrow, deep, V-shaped pits under about 2 mm across that can look like large open pores. Neither flattens much when the skin is stretched, which separates both from rolling scars.

The difference matters because depth and width decide the tool. Shallow boxcar scars sit within reach of fractional ablative resurfacing, which remodels the edges and floor. Deeper boxcars may need the edges addressed first, with focal TCA CROSS or a punch technique, before resurfacing blends the area. Ice pick scars usually run deeper than resurfacing lasers reach, so they are treated focally: TCA CROSS places a high-strength acid into each pit to stimulate collagen from within, and punch excision removes the tract altogether. Most faces carry both types, often with rolling scars as well, which is why each scar is mapped and counted before any device is chosen.

Acne scar types at a glance
Scar typeWhat it looks likeWhat lies beneathTools usually consideredWhat does not help
Ice pickNarrow (under 2 mm), deep, pore-like pitsA narrow tract running deep into the dermisTCA CROSS or punch techniquesSurface resurfacing alone; scar creams
BoxcarRound or oval depressions with sharp edges and a flat baseA block of lost dermis with intact edgesFractional ablative resurfacing; TCA CROSS or punch techniques for deeper boxcarsSubcision alone, as nothing is tethered
RollingBroad, wave-like undulations with soft, sloping edgesFibrous bands tethering the skin to deeper tissueSubcision, with filler or biostimulator support, then energy-based remodellingResurfacing alone; topical products
Hypertrophic and keloidRaised, firm scars; keloids spread beyond the original spotExcess collagen productionThe injection-based keloid pathway, silicone and selected lasersResurfacing or subcision planned for depressed scars
Flat dark or red marks (PIH, PIE)Flat discolouration with no dentPigment or dilated vessels rather than lost tissuePigment or vascular treatment, with sun protectionScar revision techniques, which treat depth rather than colour
Related reading
Follow Dr Sin Yong
InstagramTikTokYouTubeThreadsXLinkedInFacebook
Printable patient guide (PDF): Acne scar types and options — medically reviewed by Dr Sin Yong.
Dr Sin Yong · Every assessment personally performed
WhatsApp Enquiry