Unfortunately there really isn't anything we can suggest.
A snake suddenly having neurological issues and now injuries from both itself AND a rat is in definite need of a veterinarian.
I would definitely look for potential reasons for things. Some of the quick checks to make are:
Have.any new chemicals have been used around the home?
What are the current temps?
Has there been exposure to possible extremely high temps?
Exposure to extremely low temps?
Has this animal possibly been exposed to a sick animal?
Or do you have a new animal that possibly had a virus?
Could the snake have injured itself somehow prior to this? (Sometimes the self inflicted bites are because of pain)
Having answers to these may help the vet narrow down what's wrong.
I really wish there was something else I could suggest, but this isn't a simple thing you can quickly fix.