Dry Nose?

[mackynz]

it may be from rubbing on the screen lid?

That would be my vote. A picture might be able to confirm.

I'm unsure of methods to get them to stop aside from not using a screen lid. Did you do the foil top thing or use another method to cover some of it to keep humidity in? That might also help with getting him to stop, he might be viewing it as a way out right now.

Your night temps sound to low to me, but that's just my