I'm not sure what it is either but my Sky gets something that looks like this only it's in his nostrils. I clean it out about every other day and it keeps coming back. I asked my current vet what he thought it was and he didn't really know either except that his cat also gets this. He said not to worry about it unless Sky's nose had discharge. Sunny used to get this but it went away on it's own. My former vet thought it could be due to allergies.

Tess sure is a gorgeous girl. I hope that it's nothing serious.