When your skin turns red from too much sun exposure, you know you’re in for a painful ride. Sunburn can be prevented by applying sunscreen regularly. However, if you fall asleep before re-applying, you may end up with a dangerous burn. The UV rays from the sun can mutate your DNA, causing skin cancer. To prevent skin cancer, your skin should start to peel. It may take a few days, but once your skin peels, the dead, damaged cells leave your body and your body begins to repair itself.