Scarring is the bodies natural response to trauma, whereby various biochemical factors cause collagen to be laid down to repair a deficit in the skin. Unfortunately some scars may be unsightly, such as acne and keloid scars. Stretch marks are a form of scarring made when the skin is stretched faster than the body can make new skin. The deficit is filled with collagen. Keloid scarring occurs due to an individuals over reaction in healing, resulting in excess collagen formations that extend beyond the margin of the wounds. Often the original injury is very mild, even a scratch. Keloid scarring occurs in those with darker skin types, such as some Europeans, Asians, American Negros and in younger skin types. Some native tribes use this skin property to create spiritual scars as a right of passage.

Scarring can be treated and improved by topical retinoids (Vitamin A derivatives), steroid injections, appropriate lasers and topical silicon. Skin rollering has been used successfully to treat fine acne scarring. Surgery worsens keloid scars.

It should be noted that once a scar develops complete resolution is very unlikely and that all traumas to the skin can cause scarring. The best time to treat scars is as soon as they begin to form.