Margot and Karla are both right.
It has to be an antibiotic, and this is best prescribed by the vet. So take your dog for an assessment before she has the tooth removed.
Actually....I'm surprised the vet hasn't already prescribed these for her (?)
It is important to get on top of the infection now. It is not wise to give a dog general anesthesia with an infection running. It can be done, but isn't wise. Also you want to make sure the infection doesn't spread either to the jaw bone or the blood stream. Infection always places great strain on the kidneys too.
I agree with Margot...Normally, a Vet will start an antibiotic BEFORE the appointment, for infection.....Karla
When is the appt and I assume it has been checked by a Vet? You probably have to call and ask for an antibiotic.