I hope Nebo is doing OK. Poor pup. Is he acting the same? So glad you got him to the vet asap, what a wonderful mom you are! Duncan had dilated pupils once. He got out of the house when I wasn't home and when I got home, both his pupils were extremely dilated. (The vet said he was literally blind for days because of it!) They never were sure what it was that caused it but their speculation was that he got into something toxic. I think their first suspect was marijuana because his symptoms were so familiar to that type of poisoning in a dog and that type of "medication" in a human.
Not to say that Nebo was exposed to that in any way....just similar symptoms!
I hope he is doing better today. Keep us updated please!