Scars are marks left on the skin after a wound has healed. They occur when the body repairs itself following an injury, surgery, or skin condition. The healing process involves the formation of new tissue, which can differ in color and texture from the surrounding skin. Scars can be flat, raised, or indented, and their appearance may change over time. Different factors influence scar formation, including the type of injury, location on the body, and individual healing processes. Some common types of scars include keloids, which are raised and can grow larger than the original wound, and atrophic scars, which are sunken and often result from acne or chickenpox.