DS does this sometimes as well. he has 4 top and 4 bottom teeth..

I normally willl take him off if its too sore, and then go back to basics and attache him like a newborn, wide mouth etc rather than let him get on himself, as its never the deepest attachment, and thats when things get ouchy at our place.

He is not too happy when I do it though, and on tuesday he refused to feed on that side at all for about 5 minutes becuase I took him off the vreast twice as he was hurtingme too much. When he relaxed a bit I got him on with a better attachment and it was OK.

WRT how to treat the injury Im not too sure on that one other than breastmilk.