If the kitten has actually been SEEN by a vet, and that's all the vet said to do, then EITHER find another vet and get some REAL help, or take his advice. I think that I'D get a 2nd opinion, and let the vet LOOK at the cat.
Some acids can be neutralized, and THEN antibiotic creams (or ointments) be put on, to aid the healing. If this is the case, then you can EITHER put one of those "cone/elizabethian" collars on the cat, so he can't lick himself (which cats HATE, BTW) ...
OR....... you can get some Bitter Apple Spray (pet store) and spray OVER the meds, after "creaming" him. The Bitter Apple tastes bad, so the cat won't lick the cream off, if it's been sprayed over. Ointment stays on better than cream, just FYI........
Whoever threw the acid on the cat should be prosecuted for animal cruelty. People who do this "act of violence" to an animal are ONLY ONE (1) STEP from doing it to a human!
Good luck with the kitten.......Hope it feels better SOON.
50+ yrs cats / "issues"