The appearance of scars vary, depending on what they were caused by and how your body heals as a result. Scars may be flat, keloid, hypertrophic (raised) or depressed. They vary in size, shape and color. A scar can be a painful reminder of previous scenarios that we would rather not think about. They can also cause emotional discomfort if you are unhappy with their appearance. Keloid scars can proliferate beyond the boundaries of the initial skin injury and will often grow over time. They usually appear as thick, red or purple lesions. If they continue to grow, they can become tumorous, albeit benign. Hypertrophic scars are raised, reddish lumps on the skin. Unlike keloids, they do not grow beyond the boundary of the injured site.