I figured we should bring him in regardless, even though he'll hate us for a day. So, yes- first thing tomorrow morning he'll be taking a ride to the vet. I'm stopping tonight to get him a new carrier- one of the duffel bag kinds. He likes laying in luggage whenever I go on a trip, so I figured it might be somewhat easier to get him in a duffel carrier. I hope we did catch it soon enough and it's easily treatable! I'm comforted by the fact that he's at least been acting normal and doesn't seem to be in any pain or discomfort just yet. Hopefully we'll nip that right in the bud!