If the dog is vaccinated, lives indoors and is in good health, the chances that it has rabies are extremely minute. Truthfully, I would worry more about getting a tetanus shot if yours is not up to date than I would about rabies. This is a shih tzu, it's not a dog that runs loose fighting with other dogs, killing and eating small animals like rats, mice and other vermin.
A dog (or any animal) can only pass along the rabies virus if they are sick. When they are physically showing symptoms is when they are shedding the virus in their saliva. If the dog, heaven forbid, should die of ANYTHING before the 14 day quarantine is up, have the vet remove the dog's head and send it to the laboratory that your state or country uses to test for infectious diseases to make sure that it died from something other than rabies. The worst that can happen (and there is only an EXTREMELY tiny chance of this) is that IF the lab determines that the dog died from rabies, you will need to get the prophylactic vaccinations. If all is fine after day 14, go about your business and don't worry. From what you have told us, however, the chances are pretty much nil of this dog being sick.
Ghilly
If this is a domestic dog, in good health and vaccinated, I feel confident in telling you that you do not have to worry about Rabies. That being said, any animal bite can become infected so you need to watch for infection (red, swollen, pus, etc) keep it clean and should it look infected, have your doctor check it.