I would move her to a tub setup. It's cheap and it works for humidity. You also can offer the same rat again. I would only offer every 5 days.

Next I'd get a probe thermometer or heat gun to check the uth. They are often way too hot. It should read about90 on the surface above it.

Finally, if you can afford it, get her checked out at a vet. People often get rid of snakes for sometimes hidden reasons. Good to check your new snakes health