Hi there, your little person doesn't have Hand, Foot and Mouth disease, does she? My daughter caught the virus (hand, foot and mouth) last December and couldn't eat for 3 days. It is miserable, and I feel for you. Just want you to know that we've been there, and it sucks, but the virus needs to run it's course. She should start feeling better in 2 or 3 days. My daughter's mouth was filled with over 30 sores. Misery, I know. But it will pass.
I want you to know that I am not a doctor, and it could very well be cold sores, but cold sores (Herpes Simplex 1) usually happen outside the mouth on the lips and face. Nonetheless, your daughter could have a fever from the HAND, MOUTH and FOOT virus just because it is a virus, and her body is trying to fight it. Be sure to keep your daughter hydrated with Pedialyte (my daughter drank the grape). Because her throat was also covered in sores, she was having a hard time swallowing and resisted the Pedialyte. We made her take sips which kept her hydrated even if she is having a hard time with food.
I know it is hard to see your baby go through this, but it will pass. Cold drinks and warm baths also ease the pain.
L.