Cheating in Islamic exams

Salam I am writing this question on behalf of a dear friend who Is deeply disturbed. Mmy friend was experiencing depression and Istihada 2 years ago and she ended up cheating on her Islamic/Alimah exams- not all of them, a few of them. She doesn't remember 100% if she cheated or not, it was an online exam and she memorised the answer and wrote it on the paper before the exam but she doesn't remember if she referred to what she wrote or not, she doesn't remember if she backed spaced it. She has finished her course, had made sincere Tawbah and is consumed with guilt. She never called herself as Alimah, she refutes anyone who calls her an Alimah and she didn't go to her graduation.if someone asks her, she said she studied Quran and Hadith as she didn't cheat on those exams. She has been teaching on behalf of her teachers request and being doing Khidmat for the institution she studied with. She is scared to bring this up with her teachers as she doesn't know what she did. She regrets it immensely and wants to know if any of her Khidmat of Deen and teaching will be accepted by Allah, she wants to know if she should stop all Khidmat and teaching and leave the institute and just do Tawbah and have nothing to do with learning Ilm- she finds this very difficult to leave as she did Tawbah and wants to serve the Deen. If she earns any income teaching the Deen- is it Haram. Please can you guide her JazakhAllah Khair