I’d be scared to use salt with my catfish. Would myxazin work? I used it for my betta with fin rot before and it healed well. It contains 545mg/l malachite green and 340mg/l of Acriflavine hydrochloride. There is also minimal formaldehyde as a stabiliser.
One of my other woodcats are presenting another somewhat similar bump to the other one but this time right on the side of his head. Is this also scar tissue?