D.M.
If I were you I would immediately take her to the doctor. Have them assess the situation and go forward on their recommendations. There is a possibility that your daughter just has a yeast infection and she was itching herself in some manner that she doesn’t want to admit to you. Have them check for bladder and yeast infection. The important thing is to try and get to the bottom of this as soon as you can. Find out what the doctor thinks, and then start talking with the teacher. I hope works out for the best.