A suntan is actually your body’s response to UV damage and is an attempt to defend itself against additional damage. A suntan always represents skin injury and a sunburn is a sign of more severe damage. Whether you tan or burn, the sun’s UV rays can cause skin cancer and can lead to signs of premature aging and wrinkling. UV rays also suppress the body’s immune system and its ability to stop precancerous changes.
-Nebraska UNMC Medicine
Apparently, tanning beds are even worse for you.