I would consider another vet in the future, based on your original description what should have been done is a culture,The vet didn't find anything immediate but did order x rays and bloodwork. He's on antibacterial shots just in case there is something
Aside from a quick $100 what was your vet reasonning for an x-ray?
Bloodwork is debatable, unless your vet has reason to believe that the RI is a symptom for something far more serious which is possible but in reality most RI are just that well of course they first need to be diagnosed properly.
And antibacterial shots just because it's a poor excuse for a medical professional, that would not be done with a person nor a dog neither should it be done for a snake unless there is a reason and just because is not a reason.
I have always said it, be in charge or your animal's health demand necessary test and skip the one that do not make much sense.