PaulsMom,
I am with you, this is so painful
At 2.5 months, my DS got into a habit of biting down and turning his head away from me- not fun. I found that pulling his face to me quickly- instead of pulling away- forces him to release. I also firmly say, "No biting Momma," and I wait a minute before allowing him to nurse again (paired with a kiss on the head and a gentle, "I love you." Don't want him to associate BF with rebuke... just the biting!) If he bites a second time, we are done for that feed. I find now, at almost 6 months, he will occasionally start to bite and look up at me. This gives me a chance to remind him not to bite, and he most often chooses to resume eating. But that doesn't always happen- sometimes he bites anyway. It's a work in progress.
One other note: I have noticed he will nip when my supply is lower, so I also try to bump up my water intake if he's biting regularly. You may or may not find a similar connection between supply and biting.
Good luck! Hang in there, you'll figure out what's best for you and your LO.