Acne scars are permanent textural changes in the skin caused by the body’s wound-healing response to inflamed breakouts. They affect up to 95% of people who experience acne to some degree, though severity varies widely. Unlike the flat dark or red marks that fade on their own over months, true acne scars involve structural damage: either a loss of tissue that creates depressions in the skin or an overproduction of tissue that creates raised bumps.
How Acne Scars Form
Every acne lesion triggers inflammation, even before it becomes visible on the surface. That inflammation persists throughout the breakout’s entire life cycle, from the earliest clogged pore to the final healing stage. When the inflammation runs deep enough into the skin, it damages the surrounding tissue and kicks off a wound-healing process that doesn’t always go according to plan.
The key player is collagen, the structural protein that gives skin its firmness. About 3 to 5 days after tissue damage occurs, cells called fibroblasts start producing new collagen to patch things up. In healthy healing, the body lays down just enough collagen to restore the skin’s original structure. In scarring, that balance goes wrong. In 80 to 90% of acne scar cases, the body destroys more collagen than it rebuilds, leaving a depression. In the remaining cases, it overproduces collagen, creating a raised scar. Inflammatory cells are found in 77% of depressed acne scars, underscoring how central inflammation is to the process.
The longer inflammation lasts, the more damage accumulates. Prolonged inflammatory responses can irreversibly destroy the oil gland structure beneath the skin, contributing to permanent depressions that won’t fill in on their own.
Depressed Scars: Ice Pick, Boxcar, and Rolling
Most acne scars are atrophic, meaning the skin has lost volume and sits below the surrounding surface. These scars come in three distinct shapes, and knowing which type you have matters because treatments work differently on each one.
Ice pick scars are narrow, deep pits less than 2 millimeters wide. They look as if a sharp point punctured the skin, creating tiny crater-like holes, most commonly on the cheeks. Their depth makes them among the most stubborn scars to treat.
Boxcar scars are wider than ice pick scars with sharply defined vertical edges, giving them a box-like appearance. They can be shallow or deep and often appear on the cheeks and temples. Think of them as small, round or oval depressions with steep walls.
Rolling scars create a wave-like, undulating texture across the skin. They result from bands of scar tissue pulling the surface downward from beneath, giving the skin an uneven, shadowed appearance. These tend to be wider and shallower than the other types.
Raised Scars: Hypertrophic and Keloid
When the body overcorrects during healing, it produces roughly three times more collagen than normal, creating scars that sit above the skin’s surface. Hypertrophic scars stay within the boundaries of the original breakout and are most common in areas where skin is under tension, like the jawline, chest, and back. Keloid scars grow beyond the original wound’s edges and can continue expanding over time. Both types feel firm or rubbery to the touch and are more common in people with darker skin tones.
Scars vs. Dark Marks
Many people mistake post-inflammatory hyperpigmentation (the flat dark or brown spots left after a breakout) for scarring. These marks are sometimes called “pseudo scars” because, while they’re visible, they don’t involve any structural damage to the skin. The simplest way to tell the difference: run your finger over the area. If it’s flat with no change in texture, it’s a pigment mark that will fade over weeks to months. If the skin is pitted, indented, or raised, it’s a true scar. Post-inflammatory redness (pink or red flat spots, more visible on lighter skin) also falls into the temporary category.
Who Is More Likely to Scar
Acne severity is the strongest predictor. People with severe acne are roughly 5.5 times more likely to develop scarring than those with mild acne, while moderate acne carries about 2.3 times the risk. But severity alone doesn’t explain everything.
Genetics play a significant role. Having a family history of acne nearly triples the likelihood of scarring. Researchers have identified specific genes involved in both inflammation signaling and collagen production that differ between people who scar easily and those who don’t. People prone to scarring show a distinct immune response: their inflammation lasts longer and involves different types of immune cells compared to people whose skin heals cleanly.
Men are about 1.6 times more likely to develop acne scars than women. Stress levels have also emerged as a significant independent risk factor, likely because stress hormones amplify inflammation. And while it’s difficult to study formally, delayed treatment of active acne almost certainly increases risk, since every additional day of deep inflammation gives the skin more opportunity to heal abnormally.
How Acne Scars Are Treated
No single treatment works for all scar types, and most dermatologists combine multiple approaches. The best strategy depends on whether your scars are depressed or raised, how deep they go, and your skin tone.
Resurfacing Treatments
Laser resurfacing is considered a first-line option for depressed scars. Ablative lasers (CO2 and erbium) vaporize thin layers of damaged skin to trigger the body’s collagen-rebuilding process. They’re effective but require several days of downtime while the skin heals. Non-ablative lasers work beneath the surface without removing skin, making recovery faster but typically requiring more sessions. For people with medium to dark skin tones, picosecond lasers can reduce scar volume by 32 to 45% within three months with a lower risk of discoloration.
Chemical peels use acids to remove damaged skin at varying depths. Superficial peels address mild texture issues, while a technique called TCA CROSS, where high-concentration acid is applied precisely into individual scars, is particularly effective for ice pick scars. It works by destroying scar tissue at the base and stimulating new collagen to fill in the depression from below.
Microneedling and Radiofrequency
Microneedling creates thousands of tiny punctures in the skin using fine needles, triggering a controlled healing response that produces new collagen. Radiofrequency microneedling adds targeted heat energy delivered through insulated needles directly into the deeper layers of skin, combining the benefits of mechanical and thermal stimulation. This approach has shown clearance rates of 78 to 85% for active cystic scars in some studies.
Fillers and Subcision
For rolling scars and broad depressions, injectable fillers can restore lost volume beneath the skin’s surface. Hyaluronic acid fillers provide immediate improvement lasting 6 to 12 months. Longer-lasting options stimulate the body’s own collagen production over time, with some maintaining results for 18 to 24 months and patient satisfaction rates above 75% at two-year follow-up.
Subcision is a minor procedure where a needle is inserted beneath the scar to release the fibrous bands pulling the skin downward. It’s especially useful for rolling scars and is often combined with fillers or microneedling for better results. A refined version called dual-plane subcision releases tissue at two separate depths for more complete correction.
Surgical Options for Deep Scars
For deep ice pick and boxcar scars that don’t respond well to resurfacing, punch techniques physically remove the scar. The small cylinder of scarred skin (typically 3 to 4 millimeters) is excised and either stitched closed or replaced with a tiny skin graft from behind the ear. The resulting mark is flatter and more responsive to further resurfacing treatments.
What Recovery Looks Like
Scar maturation is a slow process. After any treatment, new collagen production begins within days, but the collagen composition shifts gradually. Early healing produces a softer, less organized type of collagen that slowly transitions over months into the stronger, more structured collagen found in mature skin. This is why dermatologists space treatment sessions weeks or months apart and why final results can take 6 to 12 months to fully appear. Most treatment plans involve 3 to 6 sessions depending on severity, with visible improvement building incrementally after each one.