Contact her pediatrician immediately! It could be a seizure. If they are closed, I would even go so far as going to urgent care.
It siunds like she has or is having seizures. Take her to a doctor asap to be certain. I hope she will be okay, best wishes
She need to be seen by a Dr. ASAP. I'm an EMT, it could be anything from febrile seizure, to issues with her kidneys.
Hopefully your grand baby is ok! Definitely a Dr is needed! My Step daughter started seizing after a high fever when she was two also. The ER said it was not uncommon for children and usually stops by age 5. Thankfully she had only the one.