help!

My son is almost 8 and a half months old. He has 3 teeth now. He is constantly biting me while nursing. Some times it is accidental. Some times he is starring me in the face and chomping down. He hasn't broken the skin but now my nipples hurt nursing or trying to pump. Not sure what to do. When he bites, I take him off and tell him no biting but it doesn't seem to be working. I know he is also a little young still to understand completely but any advice would help. I'm trying to make it to 1 year but this is getting so painful 😔