If you live near an ER vet like someone else said, I'd go. I live in Philly so UPenn is 20min away, if Plato ever had anything even close to this and the vet was playing fucking games he'd be at the ER without blinking an eye.
If you aren't happy with the vet, voice your concern very very loudly... or get a second opinion ASAP.
Dogs have an amazing threshold for pain/sickness, especially a pitbull. I am sure Chaos will pull through it just fine.