What's the best medication for a yeast infection? wouldn't want it to come back.

Azole drug: The usual treatment is an "azole" cream. Many OTC products are available (miconazole, clotrimazole, and others). Or fluconazole (Diflucan) by mouth, single dose. All are equally effective; choose the least expensive. Don't self treat if you don't have typical yeast symptoms (vulvar itching and irritation, with little discharge). If more discharge or odor, it probably isn't yeast, could be STD.