I don't know if you should raise or lower it until I know what it is?
I would reccomend keeping it at around 55-60% and getting your temps up, 94 warm and 85 cool.
RI's are no joke, they may start out mild but untreated they can be a death sentence. Snakes can't cough up junk like we can and once it gets the lungs they can drown. Make sure your vet does a culture of the mucos because unless you use the correct antibiotic for the specific bacteria causing the infection, you are wasting your time and stressing out a sick snake for nothing.
Best of luck