Help!! Firebelly newt sick!!!

Help pls!!!! I've had my firebelly newt for 4 years now. About a week ago I noticed a white patch on his tail. I'm pretty sure it's a fungal infection. I went to the pet store and they suggested I put in fungal medication for freshwater fishes in the water for 7 days. I changed his tank completely in case there was anymore fungal spores. I started the medication and on day 1 he was really irritated by it and kept wanting to run out of the water. The next day he was fine and started to shed his skin so I thought he was getting better. The patch started to peel. Then now on day 5 of treatment suddenly the fungal infection came back with a vengeance. He now has 3 more tiny patches on his body, the tail patch which was disappearing has now expanded and completely surrounded his tail, and he can't seem to walk properly. In a panic I put him in a salt bath yesterday night for 10 min. This morning when I woke up he still seems very sick but has more white patches on his body (these ones are different from the fungal ones, looks like his skin wants to start shedding everywhere at once) please please please help I don't wanna lose him

Hopefully the increased shedding means that he's getting rid of all the infected skin.
I would think continued salt baths, and then maybe some fridging would inhibit the growth of the fungus and allow him to overcome the infection.

Worst case you might try some store bought anti fungus medicine, but you should do careful research first as these medicines are made for fish and might harm a newt.

If the infection is caused by Saprolegnia, fridging could make recovery harder.
I would go with salt baths.

How is your newt doing?