If the dent is gone, he's probably fine, but he might be a little sore, so I'd let him be for at least a few days, just in case. Sounds like he's fine though, I'm glad.
Neosporin is technically safe & effective as an antiseptic, but like I said, don't use more than a smidgen, & not for long. It really messes up sheds. If the skin isn't actually broken, you don't need it anyway, nor the better option of Vetericyn. Diluted Betadine (povidone-iodine) is fine for snake wounds too, with no impact on sheds.
BTW I just looked up "hol-ee roller" dog toy- now I know what that is, & my dog has one, lol. (but none of my snakes do)