The fact that this idiot pet store guy thinks one shot will cure an RI is beyond stupid! Compound that by selling you a snake that he knew was sick and not mentioning it....I'd be more than ticked off personally!

Stick with the routine the vet has given you. Keep this snake warm, quiet and quarantined until it gets a clean bill of health. This is an excellent reason to quarantine all new arrivals even if they appear healthy and to always house seperately.

I'd also consider forwarding a copy of your final vet bill to this store owner and suggesting strongly that he cover it or at least part of it since he knowingly sold you a snake that wasn't healthy nor had it been given proper vet care. If this is a chain store, send another copy with your cover letter to their corporate head office.