High humidity is a good thing, it helps to keep the mucous in the lungs soft. If the humidity drops then the mucous becomes thick and your snake will have a harder time trying to get it out of its lungs.
Secondly, I have used oral baytril before for a snake that I purchased with a RI. I did get a culture though, and Baytril was found to be the correct antibiotic. Anyhow, that snake is now older, and in great health. It was on baytril for 30 days. So despite what has been said, unless it was just a random fluke... oral baytril can and does work (provided it is the correct medication, determined by a culture)