Will It Be Safe To Take Nystatin For Thrush?

Hi, I was diagnosed with thrush mouth 3 days ago. They prescribed me Nystatin 100000u/ml 3 times a day. I'm a 42 year old female, who just had a complete physical, don't smoke & has a glass of wine once in awhile. I don't understand why? Why is it so painful, I can barely open it, maybe enough for a straw, basically living on liquids cause when I move my jaw it hurts really bad. Do you think I should see another doctor or just give this medicine a chance?