Yellow Watchman with a hole in it's side!

[Albertan22]

My yellow watchman has had some kind of skin/scale irritation for awhile now. I had posted about it a couple of weeks ago and got no response. Well it's gotten significantly worse. He must be rubbing it quite a bit because he's worn a hole right through his side. It's to the point that I can actually see his internal organs now. The strange thing is, he still eats voraciously and is acting normally.

I've removed him to a quarantine tank and am treating with a broad spectrum antibiotic. I don't know what else to do for the poor guy, every time I look at him now I can't believe that he's still alive, let alone eating. Is there anything else I can do for him? Can a fish heal from an injury like this?