Goldfish mouth pimple?!?!

[mikeh123]

Im wondering what this is.. I noticed about 2 days ago that my Goldfish (Zander) had a small marking on his mouth and it has grown to this today.. Im wondering what it could be the best way to describe it is a white headed pimple.. the only thing I can say that has changed is their temperature got a bit warm today but I've made it better using ice in a bag to make the temp colder... Any help is appreciated I worry about the little guy hes so beautiful. These are the best pictures I can get (I dont have a great camera.)

[finnfinnfriend]

His nostril might be a little infected. Make sure his water is extra clean. And I would say do an aquarium salt treatment but you should ask someone more experienced with goldies about that...