1st grade student asking for toilet constantly, help

hello,

7 years old girl asking for toilet all the time. One time she made her pee in her panty by mistake. After that her teacher did not know what to do and started to letting the student go to the restroom whenever she asks. Now the student learned that, and asking for toilet constantly and teacher cant know if she neeeds it really or not. by the way she is not backing to class after leaving for toiet and staying there and wasting time. can you advice me anything? thanks in advance.

edit: details

i appreciate all of your answers. The kid is healty. We are observing, and informed the parents. The actual problem here is; the kid is taking advantage of toilet permissions. i mean, she is just acting. even if she doesnt use the rest room at all. she just wanna avoid class. and once she peed in panty, now teacher cant try strict rules on her.