Hi! I went through the exact same thing a few months ago. (My 12m dd has 8 teeth).
I am lucky that my borough has a bf support programme and so I had someone come to see us. She was amazing and had tons of great advice, which I'll try to pass on:
First, she said best thing is to stop feeding on the injured breast for a day or so, to give it time to heal. She assured me that the milk won't go away, as bf is established by this age. She said to express that breast as required, manually if it is too sore to use a pump, and if you want you can give your dd that milk too.
This was really helpful for a way to heal the breast: www.kellymom.com/bf/concerns/mom/nipplehealing.html. I didn't do everything listed, but the saline solution and bm seemed to work well. I was amazed at how quickly it does heal. I think I only had to stop for 24 hours for each. (I had wounds on both sides, so I did the worst one first, then switched).
She also reviewed latching and positioning, and recommended a position for older babies where they sit up, rather than lie down, so that there is less pull, ifyswim.
I'm trying to remember what else.., I wish I could just send her to you, she was brilliant and so reassuring.
I have these links bookmarked from that time, KellyMom and LLL, so maybe they will cover the other points I am forgetting:
www.kellymom.com/bf/older-baby/biting.html#scraping
www.llli.org//NB/NBJulAug01p143.html
www.kellymom.com/babyconcerns/distractible-baby.html
GOOD LUCK!!