A "little" Neosporin or similar product (like Triple Antibiotic ointment) & without "pain relief" is okay to use, but just keep in mind that these ointments designed for human use are petroleum jelly (aka Vaseline) based, & if you use much, they can really mess up your snake's sheds for a while.
Better thing would be the water-based & made FOR snakes ointment by Vetericyn- get the version for reptile use. You can also use diluted* Betadine (povidone-iodine) (*so it looks like weak tea) dabbed on occasionally while the minor wound is healing. Don't think I'd run to the vet for something this minor- just going by your description though & without seeing it.
UNLESS: it fails to heal- swells, drains (blood etc)- if that happens, see a vet a.s.a.p.- rodents carry some nasty germs, & this bite did break the skin on your snake, so an infection is possible despite your topical first aid.
And yes, sooner or later, this happens when you feed live rodents- they manage to turn just enough & bite back, or even squirm away- snakes have lost eyes & had other serious injuries, even life-threatening ones, from live rodents. All the best.