Welcome to YT!
Sorry to hear about your little guys behavior. I completely agree with calismama above ^ It does help a lot. Thanks to my husband and the way he plays with Teddy, he taught him that biting hands and fingers is ok. I however do not think it's funny, so what's helped me is saying ouch really loudly every time which has gotten his attention to stop. If he doesn't I will stop playing with him immediately, put him in his crate and walk away.