My spotted salamander has a sore behind his leg! Is it fungus??

[NinjaNewt]

So I just noticed a really bad sore begind the leg of one of my A. Maculatum, is it fungus? It looks really painful and I have absolutely no idea what’s going on with it! It seems like he just got it and his former tankmates (I separated them a little bit ago) seem to be fine. He’s also always been a little slow and a picky eater, but he’s always acted like that. I seriously don’t know if these are symptoms or just him being his usual self. I also handle him a lot (He’s very friendly for his species, and he’s almost never hiding, he just acts like a tiny Tiger salamander) but I always wash my hands or wear gloves. He doesn’t act like he’s in pain or anything, but it looks really bad. Please could someone reply quickly? I’m really worried!
Here’s the sore:

 

[NinjaNewt]

I guess I didn’t hit “upload” on the pictures, here they are, I dont know how it got so bad without me noticing it!

 

[Otterwoman]

Scroll down to "health and illness" and the article on wounds.

https://www.caudata.org/cc/articles/articles.shtml

 

[NinjaNewt]

I guess I didn’t hit “upload” on the pictures, here they are, I dont know how it got so bad without me noticing it!

Okay, so, I talked with a few friends in the hobby and I've come to the conclusion that this wound was caused by crickets whenever I left them in there over night. Now, I just need to know how to treat it

 

[NinjaNewt]

So I just noticed a really bad sore begind the leg of one of my A. Maculatum, is it fungus? It looks really painful and I have absolutely no idea what’s going on with it! It seems like he just got it and his former tankmates (I separated them a little bit ago) seem to be fine. He’s also always been a little slow and a picky eater, but he’s always acted like that. I seriously don’t know if these are symptoms or just him being his usual self. I also handle him a lot (He’s very friendly for his species, and he’s almost never hiding, he just acts like a tiny Tiger salamander) but I always wash my hands or wear gloves. He doesn’t act like he’s in pain or anything, but it looks really bad. Please could someone reply quickly? I’m really worried!
Here’s the sore:

Okay, its starting to scar over, and he still seems fine.