Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice. As per your query of UV rays, my advice is - 1. UV rays help in synthesis of vitamin D3, if taken in minimal amount. 2. UV rays can lead to increase in acne lesions. 3. Continuous UV exposure can also lead to cancer in long term. Hope I have answered your query. Let me know if I can assist you further.