A little* Neosporin would be a good idea (use a Q-tip to dab on the wound), OR apply diluted** Betadine (povidone-iodine) **diluted to look like "weak tea".
BEST to use would be the Vetericyn (brand) ointment made for reptiles, since it's water-based, not petroleum-jelly based (which can mess up a snake's skin- causing scales to de-laminate). I'd suggest you get some to apply for a while until this heals. (You can expect extra sheds, btw, as that's how snakes heal.)
Rat bites have lots of germs- & bites to the face can become seriously infected- watch for oozing, bleeding, swelling, failure to heal. A vet visit (for antibiotics) would be a very good idea, IMO, since the bite is near life-essential organs (eyes, brain, nose, mouth) where an infection could be serious.
More important to treat now- but if you're low-key about it, he shouldn't regurge at all- just don't pick him up- keep him relaxed & just go about applying topical antiseptic- don't make a big production out of it, to where he squirms more. Gently restrain his head but NOT with a "choke-hold" & do what you need to do. Over-restraint will just get you a battle...
Are you guys starting a rat-bite club or something? https://ball-pythons.net/forums/show...-while-feeding