The term WOUND SIGN can be summarized as a SCAR, which is a mark left on the skin after a wound or injury has healed. A SCAR is usually composed of fibrous tissue and collagen, and is formed when the dermis is damaged. Scars can be caused by cuts, burns, surgery, acne, or other skin conditions. They can also be caused by diseases such as chickenpox or measles. Scars are permanent, but can be treated with various methods to reduce their appearance.