Struggling with 1 yo BF

I had my struggles with BF in the beginning but now my baby is 13 months and we were fine… and he’s teething 4 molars at same time, and my nipples are hurting and sore.. during the feedings.. don’t know what to do this far along.. I don’t know if its just biting or rubbing his teeth… how can I make it stop hurting? I don’t feel he takes a bite at me but it’s so annoying and constant.. like really strong sucking maybe..,