ANSWER:

Of course! You’re sinful for what you had done. Repent sincerely to Allah with deep remorse and never do such a sin again. 

Prophet salla Allahu alaihi wa sallam said a person who cheats is not from among us.

One of my friend’s friend was in dire need of help in her exam. She told me to help her friend in one of the questions so I hesitantly helped her. Am I sinful for helping her? She desperately needed to pass the exam so I helped her sheikh.