For all my breastfeeding Mothers

I need help/advice I have been breastfeeding my son for 8 months and he has 6 teeth and are cutting 4 more so when I am breastfeeding him when he get done he likes to bite down on my nipple when he fall asleep so I was wounding if any mothers have been going through the same thing or have experience this before and I have been thinking about winging him off the breast to formula??? I NEED HELP!!!!