There are three primary classifications, or degrees, of burns: First-degree burns. These are often the least serious, as they only damage the very top layer of skin. First-degree burns can usually be treated at home. Second-degree burns. Second-degree burns damage both the top layer of skin and the layer underneath. They are more serious and may require medical attention. Second-degree burns often present with blisters and can leave scars. Third-degree burns. These are the most serious, as they damage the deepest layers of skin and tissue. Third-degree burns can lead to nerve damage and may require skin grafts. Third-degree burns are the most serious burns, but that does not mean first- and second-degree burns do not require immediate attention. You should always seek medical attention in an effort to avoid long-lasting negative impacts.