I refer you to the response already meted out by Rabbi Boruch Ber Yoffe:- The teacher is a Rosho.
Anyone whoever dealt with teenagers and then saw the same individual years later, knows that teenage-hood [or childhood for that matter] is a phase that we eventually grow out of as we mature, so if the teacher doesn’t know that, she doesn’t belong in a teaching [nor a babysitting] position. Period.
Meanwhile stay away from individuals out to harm us. As for the individual wishing to harm, let haShem sort them out.