Pimafix for fungus, Melafix for everything else. Massive water change followed by Tbsp. of salt per 5 gallons of water won't hurt along with a slight temp boost to encourage slime coat production, also could throw in a big wad of oak/hardwood leaves for tannins.
I hope its not start of hole in the head.
So its just from getting beat up no disease. Cant melafix crash the tank?