Possible rash on vlamingi tang?

[Vette4life04]

I have a vlamingi tang. Hes about 10-12 inches. Hes in a 300gl tank and ive had him for over a year now.... started out at about an inch or two... anyway i noticed today that he has some bumps on his face. Completely different than ick. My water parameters are all normal. And all my other fish seem just fine. Just kind of concerned any help would be appreciated.