C.B.
I have found that the best way to break a fever is to do a mix of tylenol and motrin (works for babies and teens I haven't had to use it on myself yet). What you do is get the baby tylenol and baby motrin (both liquid forms). Read the labels, I believe you give it to them every 6 hours for both. What you do is give her tylenol then 3 hours later give her motrin, 3 hours later give her tylenol, etc. Do this until the fever goes away. The reason why this won't be an overdose or harmful is because they are two different medicines that do two different things. The tylenol helps reduce fever and the motrin helps with bloodflow and reduces swelling.
This combo worked really great on my daughter, who is now almost 5 years old, when she was constantly getting ear infections while she was teething. It also worked really well for a mom of a teenager that I suggested it to. She had tried everything to break her daughter's fever and couldn't but as soon as she used the combo her fever dropped right away.
Let me know how it goes! (BTW the combo was suggested to me by my daughters doctor after I had brought her in after several ear infections. Being in the military at the time I had taken her to several different doctors either because I moved or they moved. They said it was better to let her body fight it off and build the immunities than to use antibiotics all the time and having her body build up an immunity to them. It was a test by them from a study they had referenced and it worked really well. She had fewer ear infections and fever after I did that and I haven't had to take her to a doctor for it after that. But they also said that if it didn't work to bring down the fever after a few days to bring her back in. You don't want to keep them on medicine for too long.)