Burns are usually classified into three primary types. First-degree burns damage only the outer layer of skin which causes redness, pain and minor swelling. Second-degree burns damage the outer layer and the layer underneath and it cause blisters, thickening of the skin and severe pain. Third-degree burns damage or destroy the deepest layer of skin and tissues underneath and it causes widespread thickness of the skin with a white, leathery appearance. With third degree burn, the damage is so extensive that sometimes there may not be very painful because of nerve damage.