(NSFW) If your partner had this issue during sex, how would you react/solve it?

You have great sex with whoever your chosen partner is. The only downside is that occasionally, in the heat of the moment, they will dig their nails into the back of your arm, or neck, or sometimes bite you. You do not enjoy this, and it hurts a moderate amount (not terrible). What do you do? Do you bring it up, ask them to stop, break up with them, ignore it…..lets hear it.