Aspirating those places and seeing what's in there is what I would normally expect a vet to do... Is your vet a reptile specialist? I know they aren't always available, but a lot of times non-reptile specialists really don't know what they're doing in treating reptiles.

In my experience blisters don't normally slough off all at once; they usually will dry up with the 'shell' of the blister remaining, leaving time for new skin to form underneath.