A shed could explain both the wheezing and the soaking.
I would not use PAM in the cage unless you can find mites. Though PAM is relatively safe for snakes, it's still full of all sorts of chemicals, and *might* cause complications in a snake with a compromised immune system.
If you can, hold her head and peel her lip back just a bit so you can see her gums and look for bubbles. No bubbles doesn't necessarily mean it's not an RI, and it still might be a good idea to have a vet check her out, but if wheezing is the only symptom, it is probably not serious.