Why is my bestfriend mad at me now?Help please?

She obviously likes him. She's probably jealous too. If she didn't like him she would be happy for you and not mad. Plus, he saying he isn't hot enough for her probably means he has turned her down before or has shown no interest in her when she showed him she liked him. Good luck sweetie. Just try to talk to her about it and things will hopefully work out for you.