Acne scarring occurs when an inflamed lesion ruptures deep underneath the dermis, breaking the follicle wall and spilling out the infected sebum, bacteria, and other matter into the skin. This causes the healthy skin tissue to deteriorate and immediately stimulates the body's restorative processes to repair the damage. In order to do this, the body produces collagen to replace the injured skin; however, the results are never as smooth in texture and appearance as the skin once was.

Sometimes the body produces too much collagen which in turn creates a raised clump of skin tissue on the surface. This is called a hypertrophic scar. This type of scarring is more commonly found on the back and chest. In contrast, there are other types of acne scars that create a pitted appearance. Deep, crater-like scars are known as ice pick scars and pitted scars that are shallower are called atrophic scars.

Picking at or squeezing deep blemishes is the main cause of rupturing the acne lesion, which can lead to scarring.

Genetics also play a role in the development of acne scars. The genes we inherit from family members can make some people more susceptible to scarring. Also, if you have family members with a history of severe acne, which is the main cause of acne scars, you are more likely to develop the condition.

If left untreated severe acne can cause skin damage and scarring. Skin care professionals recommend seeking acne treatment as early on as possible to help reduce the chances of permanent injury to the skin.