A burn is an injury to the skin or other tissues caused by heat, chemicals, electricity, or radiation. Burns are classified into three degrees: first-degree burns affect only the outer layer of skin, causing redness and pain; second-degree burns damage deeper layers, leading to blisters and swelling; and third-degree burns destroy all layers of skin, potentially affecting underlying tissues. Treatment for burns depends on their severity. First-degree burns can often be treated at home with cool water and over-the-counter pain relief. More severe burns, such as those classified as second or third degree, may require medical attention, including bandages, antibiotics, or even surgery.