Urgent! Toes and tail tip missing on really skinny axolotl, please help :(

[Axolotlmom96]

Hi everyone,
My axolotl lemon who is about 7-8 months old has always had a problem with eating and as a result is really skinny. A few days ago I noticed the tip of her tail missing as well as one toe on one foot and most of her toes on another foot. There are no obvious signs of irritation around either and the skin looks normal, to me at least. I put her in the fridge for a few days to help with healing, but I have a few questions to ask everyone on here.
1. How would I be able to tell if these are an infection or a fungus? Should I preemptively treat her for either of these and using what products?
2. Do these look like bites? She lives with another (same age but almost double her size) axolotl and they have gotten on well since being rescued together.
3. Is it safe to fridge her with her being this skinny? She seems to have gotten even thinner in the fridge and of course now will not eat at all since her metabolism has slowed because of this.
Thank you very much, any and all help is appreciated!
(Also if anyone has tips on how to help her eat/gain weight that would be amazing)

Attached are photos of her toes and tail, the red stuff underneath her are blood worms I tried and failed to feed her

 

[NexSocius]

First up, what are your water parameters?

How long is she?

What substrate are they on?

When was the last time she pooped?

Next, I think you should check every item in your tank for sharp edges- run your finger over every inch and feel if it’s sharp- they have soft skin and a single jagged point can cut them apart.

 

[Giuseppe]

^^^agree we need all the info Nex asked for to help but looking at the photo it looks more like bites than fungus or infection. Large size differences can be a big problem even of they've gotten on before I'd definitely keep them separate. Keep in a separate tub and work on getting them too eat, as long as the temp of the room is ok I think it's more important the axolotl eat than be fridged. Keeping in a separate tub with at least daily water changes will help you monitor poop and behavior