A burn is damage to the skin or tissues caused by contact with an electrical current or a hot source. Burns can be classified as First,Second, Third and Fourth degrees. First-degree burns involve only the outer layer of skin, which is the epidermis. These burns usually appear red and swollen. There is no blistering with first-degree burns. These burns usually heal within 3-6 days without permanent scarring. Second-degree burns involve the epidermis and some or all of the dermis.