Hey, hold up. Can you post some photos of your axolotl and their tank? I want to see if it is definitely fungus. Also, is your tank fully cycled? What kind of filter are you using? Do you own adequate water quality testing stuff?
IF you do have a bad fungus issue, I can actually help with the salt bath thing. How old is your axolotl and how long? I have an almost 3 year old adult female, she's big, so the water volume and salt amount is different for her. Do not do a salt bath before you are SURE it's fungus.
Show us your little guy and let's take it from there.