If your vet did not include you in your pet's treatment plan, if you have no confidence in this vet then by all means find another vet as soon as possible and have the snake looked over.

You can phone your old vet's office, tell them you are coming by and you want copies of all this snake's records (or any animal of yours they have treated). Make sure those records clearly state what meds were given in what dosages and to treat what specific health issue.

They might charge you a fee for copying those files but as far as I know, in the end, they have to give them up to you. If they refuse, contact the board in your state that licenses and oversees DVM's.