Neosporin is ok in light moderation and shouldn't be used over and over again as it softens the scales. Betadine will work just the same if not better without harming your snake.
It doesn't look like a bite to me. I say the rat scratched your snake. It most likely kept kicking its hind legs and flung a scale off. In my experience, most rats coiled wouldn't even be able to bite since they're too busy trying to breathe, even when your snake bites the butt.... My snakes bite both heads and butts when coiling and I've never had a rat attempt to bite. They were more concerned with kicking to get away...
The bumps could be from the rat claws piercing the skin though the scales. Rat claws contain bacteria that will irritate where its touched. If the bumps are from the claws, it will clear up on its own.
To avoid future injuries, you can feed smaller sized rats more often instead if larger prey and less frequently. Weanling pups and small rats are harmless.
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