A scar is the body's natural way of healing and replacing lost or damaged skin. A scar is usually composed of fibrous tissue. Scars may be formed for many different reasons, including as a result of infections, surgery, injuries, or inflammation of tissue.Scars may appear anywhere on the body, and the composition of a scar may vary-appearing flat, lumpy, sunken, colored, painful, or itchy.here are many different types of scars, including the following: 1  keloid scars. 2  These are thick, rounded, irregular clusters of scar tissue that grow at the site of a wound on the skin, but beyond the edges of the borders of the wound. 3  They often appear red or darker in color, as compared to the surrounding normal skin.