Hello thanks for asking from HCM I can understand your concern. After reading the detailed history you have written I can tell you that most likely her symptoms are occurring due to performance anxiety. This anxiety is part of social anxiety and usually results in poor performance in studies and in job. She makes a lot of preparations before exams but on exam day she becomes anxious and even skip exam, and these are features of anxiety. I would advise you to take her to a psychiatrist for treatment of anxiety. In most individuals relaxation exercises, breathing exercises help in reducing the symptoms in anxiety provoking situations. In other medicines like propranolol, atenolol etc can be used on SOS basis. These medicines help to reduce the symptoms of anxiety like tremors, palpitations, sweating and result in increased confidence. If situation persist even with these medicines then SSRIs are used for treatment. Medicines like Sertraline, Paroxetine etc are used regularly for anxiety. Visit a psychiatrist for prescription of drugs. Thanks, hope this helps you.