Well...obviously the first point is, you shouldn't keep a snake you cannot adequately take care of. And if you can't get it treatment when its sick, I think that falls under that category. Sorry...just my opinion.
Secondly, stuff from the nose isn't good. Not at all. He needs to see a vet, the sooner the better. Respiratory infections can go from easy to fix to beyond hope in a matter 24-48 hours. Has he made the noise again? What kind of noise was it, was it whistley or more of a raspy/gargle sound?
90% humidity is too high, pinkys are way too small. How big is the snake? Even a hatchling can take more than a pinky. I hope you're at least saying pinky rats and not pinky mice.
A pic of your snake and setup would help a lot here. Your temps sound ok.
