OMG!! Please help me and my Banjo!

so basically i moved him to my corydora breeder i think it all started by getting nipped by my semi aggressive yo yo loaches, giving the catfish its stress.

There after a week went by i gave half doses of melafix.

Then i started to notice huge white sore on him, they are so big i almost thought it was Hole in the Head but with no rwports on that i put the thought to the side.

But i still dont know what im dealing with unfortunately i have no hospital tank so doing this in my breeder is my only option. As my 33 gal is at max capacity. And treating one fish out of around 20 wasnt ideal.

So rn im stuck between using either mela or Pimafix. I need so clarification.

any chance of a picture that is clear and in focus?

what is wrong with the fish, is it eating, pooping, breathing heavily, etc?
how long has it been sick for?