I understand your pain, I had that happen as well. I could always tell when she was about to bite because she would stop & her bottom lip would kind of quiver and so I would immediately w/draw my breast and say NO firmly, not men or loud, but firm. And if she did get a bite in, I would w/draw the breast & flick her on the lip again with a firm NO. That worked really well.
As far as supplementing, not that experienced with that, she never bit me hard enough to make it where I couldn't nurse. I do know that it does appear that babies will nurse less once formula is introduced, however, if it weren't available after you heal, he may go back just fine. Have you even tried nursing? My right nipple cracked & bled so much and hurt to have the nursing pad touch it. When she was latch on, it would hurt but once she got going, it was fine. Lanolin worked great at healing it so you may want to try that for this situation.
Best of luck to you. I loved nursing my 5 children, but only one did I make it past 3 months and it was with the biter, LOL. I nursed her 18 months and yes it was very enjoyable for us both.