Sunburns are caused by UVB, burn-producing rays that cause most skin cancers. These are the rays that damage the skin surface, and cause you to blister and peel. Damage also can be caused by UVA rays, which shoot deeper into the skin. These burns heal without leaving scars, but peeling may take place within a day or two. Many sunburns, whether mild or severe, are first-degree.
Mild sunburn causes the skin to turn red, but the redness disappears in a few hours or days.
Severe sunburn produces blistered skin and may be accompanied by chills, headaches, dizziness and fever. The remaining part of the dermis usually allows healing without scarring, but if the burns are extensive slight scars can remain. They can cause tissue to blister or turn black. Get out and stay out-of the sun. Cool the burn, by applying cool, wet compresses for 10 minutes at a time several times daily.