A third-degree burn is a serious type of burn that requires immediate medical attention. It is also referred to as a full-thickness burn, as it damages the top layer of your skin (epidermis), the middle layer of your skin (dermis), and the layer of fat underneath your skin (hypodermis) . Third-degree burns can also damage your sweat glands, hair follicles, and nerve endings. Unlike first- and second-degree burns, you won’t feel immediate pain if you have a third-degree burn because the burn destroyed your nerves. Symptoms of a third-degree burn include leathery, dry, and discolored skin that’s white, black, or bright red, as well as swelling. Common causes of a third-degree burn include exposure to extreme temperatures, a chemical, or a light source. Treatment for a third-degree burn requires immediate medical attention, and you should not wait to visit the emergency room.