Those grey spots are just sensory pits. That is usually where HITH will start. The little pin prick holes will start to erode and get larger. Thats when you need to worry.
He actually has had HITH. Its a continuing effort to keep it at bay. He's such a picky eater, all he'll eat is pellets. And earthworms.
And live bugs. But i hate touching bugs or getting near them, so pellets and worms will have to do.
But especially as Oscars get older, they seem to be very suseptable to it.