Babies often change their latch when they're teething and as they get used to the feel of teeth. There's a FAQ on teething and how it changes things, if you want to check it out. With teeth, you sort of have to start from scratch again, meaning every time you feel her using the teeth, you have to break the latch and start over. She's now at the age where she can understand better, so you can also reinforce it with "no teeth". Some positions are more comfortable for sure, so do that until you heal - but remember than any breaks in the skin can make thrush more likely, so keep an eye on it...
It's very possible to nurse comfortably with a mouth full of teeth! My lo was 2 when she stopped nursing, but I remember we had some adjusting for a while when they first came in.