Your the one who tell it to anyone so that they know his/her condition so that teachers know the reason why she always absent.

Help her study before the exams. Make sure she has good notes and support from her friends. As long as she has one good person on her side who helps her and guides her to do good, she'll feel better about taking the exams. Just stay by her side and it'll get better.
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This is the better answer.  I can't help but post this comment, and vote 5-stars (teary-eyed here.)  This can be a simple yet caring answer for those whose grades and presence in school are affected because of bullying.