Record every time she harasses you, or gives you a dirty look. If she starts talking crap to you, record that too. If it gets worse, talk to a conselor or a teacher.
It seems you do not know why she is doing this, and neither do we. Becareful, and do not do anything to make her confront you.
Lastly, do not try to suck up to her. Ignore her the best you can. If you did see a chance to solve the tension, do so. But if there is no chance, do not try to make one. It will not work.
But whatever you do, record things, write it down. Date and time, and who was present to see it happen. If it continues and you find that you can not cope, see the help of a teacher. Present the little notebook you used to record all the incidents of harassment, and so on.
Ignore her, but do not ignore the problem. Becareful.