How many days is normal for a fever?

My 12 month old daughter has had a fever for 3 days now (between 100 and 102 F). I took her to the ER and to her pediatrician already. Her pedi said it looks like it's a gatrointestinal viral infection. But to bring her back in if the fever doesn't clear up after 5 days.

The fever has only gotten slightly better, and ibuprophen and Tylenol are hardly working. My daughter doesn't have any other symptoms, besides a few diapers of diarrhea looking poop.

But my mom is chewing me out because she says she's had a fever too long. She says fevers are dangerous and can damage the brain. That she can end up not being able to talk permanently. And that we've (me and my sister) never had a fever that long (which I think is bull) because she made sure the fever went down. She's also saying that I'm not even worried. Of course I'm worried, but the doctors say she's going to be okay. AND my daughter plays happily and eats. Today she even seems a little better, although she still is hot and has fever still.

My mother is giving me a hard time and saying I should go to her pediatrician and demand I ask for a letter to take her to Children's Hospital so she can be under observation.

My mommy's instincts tell me she's going to be fine. But what I say doesn't matter. 🙄 (I'm a single mommy and live with my mom).