dog bit a rat, rat bit back?

i live in chicago which has a ton of rats. anyways, walking home tonight when i was locking my gate, my dog got a hold of a rat. he probably let it go in 3 seconds and was spitting blood, and i just figured out he has a cut on the inside of his mouth from this ordeal. he has lepto and rabies vaccinations and didn’t get a piece of the rat as far as i know- should i be concerned? should i opt for vet attention? i never thought the little sh*t would actually catch one.