Do not assume automatically that it is the evil eye. Try ruqya, but take her to a doctor as there might be some vitamin deficiency. You can also ask her to recite ruqya on water and wash her hair and drink from it a number of times per day:
Kindly refer to the following link(s): https://www.assimalhakeem.net/what-is-ruqyah-and-how-one-should-do-it/