Praise be to Allaah.
There is nothing wrong with a student asking a teacher for help outside the classroom to teach him and help him understand the subjects he is studying, whether that is with his own teacher or another teacher. But if the regulations of the school do not allow that, then the student should adhere to the regulations that concern him. But if there are no such regulations, then there is no reason why he should not have some teachers to tutor him outside of school hours in his home or in the mosque. There is nothing wrong with that.