According to the given passage,
Over exposure to UV rays causes skin damage or even cancer.
(If you need further explanation)
Over exposure to UV rays also causes Sunburn (or erythema); is redness of the skin, which is due to increased blood flow in the skin caused by dilatation of the superficial blood vessels in the dermis. High UV doses may also results in edema, pain, blistering, and peeling of the skin a few days following exposure. Other effects includes Suppression of the Immune System, Damage to the Eyes, etc.
