I would follow the recommendations of a qualified reptile vet.
You're going to get too many conflicting opinions here - most of them will not be based on experience, but what was heard or read from forum to forum.
What I have been told by two vets - both real good ones - is that unless your humidity is incredibly high or incredibly low, don't touch it. Follow the medicating regimen of the vet and do everything in your power to lower the stress in your animal.
On of the many things that leads to a RI in snakes is the fact that people mist the crap out of their enclosures in an effort to achieve a humidity the snake does not require. Couple this excess humidity with the bad ventilation in most tubs and you create a breeding ground for bacteria.
I had to nebulize an anthill python that came to me with a bad RI. The vet was very explicit in her instructions that once the nebulizing session was done to make sure that the tub was ventilated of all excess moisture. Her explanation was that increased humidity is not good when you are trying to fight a bacterial infection. The only thing I've ever been told to increase is the heat.