A second-degree burn is a mild to moderate burn that affects the outer layer of the skin (epidermis) and the second layer of the skin (dermis) . It is the most common type of burn. Second-degree burns are caused by a heat, chemical, or light source that destroys and goes through the first and second layers of the skin, causing damage to the cells in the skin. Symptoms of a second-degree burn include deep red to dark brown skin discoloration, blisters, shiny and moist skin, pain or discomfort, swelling, and layers of skin peeling away. Second-degree burns can take one to three weeks to heal, depending on the size and location of the burn. It is possible to treat most second-degree burns at home, but it is recommended to visit a healthcare provider if the burn covers a large area of the skin (more than 3 inches in diameter) or affects the face, hands, feet, or genitals.