UPDATE!
It's been a while since I've been on here, so I wanted to share the good news! I took Wilson back to the dr. He said he believed that the humidity was still too low, and that the inflamation I had noticed around his nostrils wasn't an infection, but a little bit of old shed that was stuck in there. He was right! He got a little thing and picked it out. I would have never guessed that!
Anyway, he put Wilson on an antibiotic cream for 10 days, and now Wilson is doing great! I have been keeping the humidity at around 70%, since 50-60% wasn't cutting it. I also am misting him more often now, and to Wilson's delight, went out and bought a little tank heater to put in the water bucket for his mister, so that it mists warm water now. He's not yet eating like a little pig, but he is eating on his own, which is a big step forward!!
I'll try to post some pictures when I get the chance.
Thank you so much to everyone who offered any kind of help or advice, I really appreciate more than you know!!!!! (and so does Wilson!)