Got a filling on the right side of my mouth and I think the dentist messed up my bite? It hurts a lot.?

My girlfriend got a filling redone (from silver to composite) 2 weeks ago from this dentist who didn't seem like the brightest crayon in the box..anyway she had a tooth on the top RIGHT side of her mouth and now she has knife-stabbing pain on the LEFT side of her jaw - from her side burn to her cheek. She read somewhere online that the dentist could have messed up her bite and now her muscles are spazzing and hurt as a result. Could this be possible? She doesn't have an abscess and her teeth look fine but she's in a lot of pain and scheduled an appointment with a different dentist for this Friday. What should we do? Should she be worried? Could this even be the issue or could it be something else? (It's not TMJ so if you're going to answer with that then save it). Thanks in advance!