@xinfenkou6 You can find information about the types of UV at most scientific organizations such as the skin cancer foundation. It mentioned that in ordinary bathroom mirrors, the UV-A light is reflected just fine, but UV-B is attenuated, and UV-C light is absorbed by the glass. Also the reflectivity of various metals is indicated there.
He can't and he won't do anything to your parents! People like him try to get their pray by telling them lies to control them.
The best thing you can do is tell your parents about it, avoid walking around alone and above all, do NOT do anything ON YOUR OWN.
Try Tylenol or midol and a heating pad. Also as soon as you feel it coming on try some relaxation techniques. Try to stay calm and don’t fight the pain just try to keep your muscles relaxed. Hot baths help too. But if you find that every month you’re in unbearable pain talk to your mom or dad. Get to a doctor and don’t be scared an exam is really not that bad. They can see if everything is ok and possibly prescribe you birth control pills in order to regulate your hormones, make your flow lighter and less painful. Good luck. I’ve been there.