A sunburn is a kind of burn that happens when skin is exposed to sunlight for too long. The ultraviolet part of sunlight breaks down natural chemicals in the skin. This makes the skin become red. A sunburn can be painful. Sunburns stay for days or weeks.
People with lighter skin have more sunburns than people with darker skin. This is because of a dark pigment called melanin that protects the skin. There is more of it in dark-skinned people than in light-skinned people. Eventually, if exposed to too much sunlight, skin cancer may develop.