Dry nose or white dust on nose?

[blubudgie]

I noticed recently that my bp has some dry nose or dust on his nose im not sure which.
The edges of his mouth are also darker than usual but I'm not sure if I'm just being paranoid.
He is a 1 year old bp, 600 grams. He skipped the past two meals so he hasn't eaten for about 2-3 weeks. He doesn't normally skip meals, and if he does he usually only skips one. I recently switched to Aspen bedding this month, could he be having a reaction to that?
Temps are 90 hot spot and 75- low80s cool side. Humidity is high 60s-70 percent.
i have some pictures that I need to figure out how to post

thanks for the help

[blubudgie]

[blubudgie]