8 month old fever of 102.3?

My Gracie got vaccinated yesterday, 2 shots. She was fine last night but woke up this morning with a high fever. I called the doc and they said to give her tylenol and see what happens, but they didn't confirm or deny when I asked if it could be because of her shots. So I gave her tylenol and then a cool bath. She really lightened up in the tub and now her temp is 98.8. Im afraid that when the tylenol wears off, it will spike again. What should I do?