Sick High Finned Pleco?

About a week ago I added a new Pleco to my tank because my friend couldn't take care of it anymore. It was just a regular pleco. I have had a High Finned Pleco in my tank for about a year. I noticed the other day it started to get a white spot on his nose. It looked fuzzy so I umed it to be a Fungus, I started treating the tank with Melafix and this morning I woke up and noticed there was a hole in his nose now, or maybe even an indent. Could this be Hole In the Head? All levels are normal I mean I am medicating my tank so some are a little off. The carbon isn't in the tank,and i also have a Raphael Catfish, 3 Australian Rainbow fish and a Gold Gourami in my tank, all of them are at least 6 months old. But I dunno what to do about my pleco he doesn't seem to be getting better. Thanks for the help