I agree with Opal. Sometimes the hair follicles are just more noticeable on some people. It's no big deal. I don't think you should have to let him know about it. It would be kind of like letting him know that you have breasts and a vagina too, kind of a given, you know?
If your boyfriend is bothered by it, then he might not be ready to do anything sexual anyway. Being ready to do sexual things should involve some knowledge of anatomy, some knowledge that all people are a little bit different, and being comfortable with those differences.