Scales coming off definitely sounds pretty bad. In most cases, I'd say to make sure you go to a vet that knows snakes. However, with a bad burn, waiting until Monday doesn't sound like a good idea. Most areas, unless you are really out on the country, will have some sort of emergency vet around that is open 24 hrs, and at least in my experience, those will see any type of animal. You might try looking it up online or in your phonebook. If you find one, maybe they can at least give you advice over the phone and help you first of all figure out how much of an emergency this is, and second of all help you find a vet who at least knows enough about reptiles to see an emergency case who is open on Saturday.