Illness/Sickness: Salamander missing chunk, No tank mates?

Hello, I seem to have a "Sick" Salamander, I have had him for over a year, and as to my knowledge his way of living has not changed, He has a wound well,wounds, about 5 days ago the wounds started out small and one got larger, looked like something took a bite out of him,I started treating him, Quarantined him washed his wound with prepared saline solution from the pharmacy, with an eye dropper, only on the effected area, waited 5 minutes and then rinsed with spring water 2x day ( I have only ever used spring water for everything involving him) He was healing nicely, and the first wound has improved, but now the small ones is getting worse, not deeper but looks if it is widening. There seems to be no puss, and definitely NO fluffy stuff, Here is the kicker, He seems to not be effected by this at all, he eats like a pig( as usual) hes curious of his new surroundings, and even tried to escape, using his tail to balance his entire body against the glass to crawl up. So any idea?

Ps, he has no tank mates,

The first picture was of the first bad wound, the second was taken a couple of hours ago.

Have you tried Neosporin on the wound?

I had a juvenile tiger I got as a rescue years ago with an absolutely mangled tail. It looked like he'd been run over with a bicycle; and I'm surprised it didn't fall off. I really debated amputation. I spent weeks debriding it and picking off the gross parts. It healed up fine, took maybe 2 months, with a sterile setup (paper towels) and a dab of neosporin occasionally on the worst parts.

Is Neosporin the same as polysporin? I have thought about it, but i was afraid of using anything but fresh saline and spring water.

Polysporin is the same. Just be sure to use one with NO pain killers. Just simple antibiotic ointment.