A second-degree (partial-thickness) burn occurs when the second layer of skin (dermis) is burned. The burn may be very red, with blisters and swelling. If the burn is smaller than 2-3 inches in diameter, it may be treated as a minor burn using the guidelines shown above. If the burn is larger, or is located on the feet, face, eye, ears, major joints or groin, seek medical attention.
A third-degree (full-thickness) burn involves all layers of the skin and can lead to permanent tissue damage. The skin may appear charred, blackened or white, with a dry or leathery texture. Seek medical attention immediately in cases of third-degree burn.
Source: American Burn Association