Acne scarring happens when inflamed breakouts damage deeper layers of skin, and the body’s repair process produces too much or too little collagen to fill the wound properly. Nearly 47% of people with acne develop some degree of scarring, and in 80 to 90% of those cases, the scars are depressed rather than raised. Understanding what drives this process can help you take the right steps to minimize permanent marks.
How Inflammation Leads to Scars
Every acne lesion, even a small one, triggers inflammation beneath the skin’s surface. Inflammatory cell infiltrates have been found in 77% of depressed acne scars, which tells us that the immune response itself is a primary driver of tissue damage. The inflammation doesn’t just appear when a pimple turns red and swollen. It actually begins much earlier, in the microscopic clogged pore stage, and persists through the entire life cycle of a breakout.
When an inflamed pore ruptures or leaks its contents into surrounding tissue, the body sends immune cells to clean up the debris. Those immune cells release enzymes that break down collagen and elastic fibers in the skin’s structural framework. The acne-causing bacteria on your skin accelerate this process by stimulating skin cells to produce even more of these tissue-dissolving enzymes, along with inflammatory signaling molecules that amplify the damage.
Once the inflammation subsides, your skin attempts to rebuild. This is where the process can go wrong. Healthy wound healing produces new collagen in a structured pattern that closely resembles the original tissue. In acne scarring, that rebuilding is disrupted. The skin either fails to produce enough new collagen (leaving a depression) or overproduces collagen in a disorganized pattern (creating a raised scar). The deeper and more prolonged the inflammation, the greater the chance that repair goes off track.
Why Most Scars Are Depressed, Not Raised
The vast majority of acne scars, roughly 80 to 90%, are atrophic, meaning the skin dips inward. These form because the enzyme activity during inflammation destroys more collagen and elastic fiber than the body can replace. Research shows that in atrophic scars, levels of tissue-dissolving enzymes spike while the molecules that normally keep those enzymes in check drop simultaneously. The result is skin with less collagen and fewer elastic fibers than the surrounding healthy tissue.
Atrophic scars come in three distinct shapes. Icepick scars are narrow, deep, V-shaped pits that extend into the deeper layers of skin. Boxcar scars are wider with sharp, defined edges, forming a U-shape. Rolling scars have sloping, wave-like edges that give the skin an uneven, undulating texture. Many people have a mix of all three types.
Raised Scars: Hypertrophic and Keloid
A smaller percentage of acne scars are raised above the skin’s surface. In hypertrophic scars, collagen production runs at roughly seven times the rate of normal, uninjured skin. That excess collagen is predominantly a different type than what healthy skin contains, and it arranges itself in flat, parallel bundles rather than the interwoven “basket weave” pattern of normal tissue. This is what gives raised scars their firm, sometimes shiny appearance.
Keloid scars are an extreme version of this overproduction. The cells responsible for building new tissue show altered gene activity, churning out collagen and structural proteins at abnormally high rates. Unlike hypertrophic scars, keloids can grow beyond the boundaries of the original breakout and are more common on the chest, back, jawline, and earlobes.
The Biggest Risk Factors
Not everyone with acne develops scars. Several factors determine whether your skin heals cleanly or with permanent marks.
Severity of acne. The more inflamed and widespread your breakouts, the higher your risk. Deep, cystic lesions cause more structural damage than surface-level whiteheads or blackheads.
Delay in treatment. The time between when acne starts and when effective treatment begins is one of the most important modifiable risk factors. Every month of uncontrolled inflammatory acne gives the skin more opportunities to accumulate damage that heals improperly.
Repeated flare-ups. Relapsing acne compounds the problem. Each new round of inflammation in the same area adds fresh damage on top of tissue that may already be trying to repair itself.
Male sex. Males have a statistically higher likelihood of developing acne scars, likely related to hormonal differences that influence both acne severity and inflammatory response.
Young age at onset. Developing acne at an earlier age means more cumulative years of inflammation before treatment, which increases overall scar risk.
Genetics Play a Significant Role
Your genes influence both how severe your acne gets and how your skin heals afterward. Twin studies have shown that about 81% of the variation in acne can be attributed to genetic factors rather than environment. That’s a remarkably high number and helps explain why acne severity and scarring tend to run in families.
Researchers have identified specific genetic variants linked to scarring risk. Variations in genes that control those tissue-dissolving enzymes and their regulators appear to make some people more prone to scar formation. One variant related to an enzyme inhibitor was associated with a 23% increased risk of acne scarring. Another genetic variation was found significantly more often in people with severe acne who went on to develop scars, suggesting that certain gene profiles make the skin less able to regulate the breakdown-and-repair cycle properly.
If your parents or siblings had significant acne scarring, your own risk is likely elevated, which makes early and consistent treatment even more important.
How Picking and Squeezing Makes It Worse
Manually squeezing or picking at breakouts pushes inflamed material deeper into surrounding tissue, widening the zone of damage. It can also rupture the wall of a clogged pore that might have resolved on its own, turning a superficial blemish into a deeper wound. Picking creates new wounds or reopens healing ones, leading to bleeding and scarring that wouldn’t have occurred if the lesion had been left alone.
For some people, focused picking at a specific area can continue for extended periods, causing significantly more skin damage. Even casual squeezing of a pimple introduces bacteria from your fingers and nails into an already compromised pore, extending the inflammatory process and increasing the chance of a permanent mark.
Red Marks vs. Permanent Scars
Not every mark left behind by a breakout is a true scar. Post-inflammatory redness and dark spots are part of the normal healing sequence and sit earlier on the timeline than permanent scarring. These flat, discolored marks don’t involve structural changes to the skin. They fade over weeks to months as inflammation fully resolves and excess pigment is cleared.
A true scar, by contrast, involves a change in the skin’s texture: an indentation, a raised bump, or a visible pit. The distinction matters because temporary discoloration will improve on its own, while textural scars represent permanent alterations in collagen architecture that generally require professional treatment to improve. If you’re unsure whether a mark is a scar or post-inflammatory discoloration, run your finger over it. If the skin surface is smooth, it’s likely a temporary mark. If you can feel a dip or a bump, it’s a scar.
Why Early Treatment Matters Most
Because treatment delay is one of the few risk factors you can actually control, getting inflammatory acne under control quickly is the single most effective way to prevent scarring. Current clinical guidelines strongly recommend topical treatments that unclog pores and reduce inflammation as first-line options, often in combination to target acne through multiple mechanisms at once.
For acne that is severe, causing scarring, or not responding to standard treatments, guidelines strongly recommend isotretinoin, which reduces oil production, inflammation, and bacterial activity simultaneously. The goal with any approach is the same: shorten the duration and intensity of each inflammatory episode so the skin has less damage to repair and a better chance of healing normally.
Waiting to “outgrow” acne or cycling through ineffective treatments while inflammation persists gives scarring more time to accumulate. Each individual breakout is a small wound, and the fewer of those wounds your skin has to heal, the lower your lifetime scar burden will be.