Scars form when the dermis is damaged. The body forms new collagen fibers naturally to mend the damage, resulting in a scar. The new scar tissue will have a different texture than the surrounding tissue. They are formed after a wound is completely healed.

Scars take many forms including raised, pitted and stretched. A raised scar is due to overproduction of collagen. A stretched scar can occur when the skin is under higher tension during the healing process. This is common when the wound is near a joint.