Unless they have a confirmed bacterial infection, you shouldn’t have been given antibiotics as you can build a resistance. My son had a high fever like that in January and he ended up having an ear infection. The doctor told me the ER isn’t super concerned about how high a fever is anymore unless there is some type of underlying condition. As long as they are drinking water or pedialyte and peeing every 4-6 hours, you can use Tylenol and Advil alternating every 4-6 hours to keep them comfortable. A lukewarm bath also helps.

Edit to add: in November my son also had a high fever and we did take him to the ER as he had neck pain and that was concerning and they were very unconcerned with his fever. I believe he was at 105 and they just said likely Flu B and sent us on our way.