What is the definition or description of: sun damage?

UV radiation: Is invisible to the naked eye but when skin is exposed to it, damage to the cellular dna is caused. Over time and multiple/long-term exposure, skin cells can show signs of damage (actinic change) that can progress to skin cancer (3 main types). Severe sunburn can cause melanoma, the most deadly kind of skin cancer, and tanning beds can do the same. Squamous and basal cell cancers are more common!

Healthy Skin: Sun damage takes two forms. The sun damages the skin resulting in loss of elasticity along with wrinkles and discoloration. Over time it also brings on skin cancer if the skin has been repeatedly damaged and there is no sun protection. Hence, use sun block.