dojo loach with facial tumor?

[Phoenixphire55]

So I got a dojo loach at Petco and when I got him home I realized he had a whitish / pinkish spot on his face. I have been treating him with pimafix and melafix for a little over a week and the spot is still there and has gotten worse. Now there appears to be some kind of growth extending off of the sore. It literally looks like the loach is growing a sharp little horn. It is very weird looking and he basically looks like a dragon or something with this weird little horn thing. Any idea what this could be and how I can get rid of it?

Sorry that I can't provide pics. Please don't suggest I return him to Petco because I don't want to do that.