The test you cheat on only tests what you already chose to become.

Cheating risks a grade, but it also settles a question about who you are willing to be when nobody is checking. The subject matter is almost beside the point. Each small decision like that is a vote, and enough votes add up to a character you never consciously chose. That is the result the test actually returns.

If you feel far enough behind in a class to be considering it, say so to the teacher before the exam rather than after. Ask for help early, even when it is embarrassing. Take the honest grade and keep the person.