I have had a snake drop a tooth at the vets once but never had an infection like yours developed. I have done a lot of rescues over the years and seen all kinds of issues but this isn't something I have encountered yet. It is great when you find a good vet I too am fortunate to have a great vet near me whom is also reasonably priced. My bearded dragon has had a number of visits and his antibiotics and visit costs often run about the same 50$. keep us posted as she improves!