My skin gets really clear after going to the beach. how come?

Acne: Uv light is known to help acne but when you're in the sun, you cannot calculate the right dose of it, so along with some advantage, there are also disadvantages such as overexposure with resultant risk of burns, increase risk of skin malignancy, etc. I would not just go to the beach to tan to get acne better. Talk to doc about uv therapy for acne whether it is right for you or not.