First of all, wrong forum.
Second of all, it sounds like you failed CIS, and you think it was because you knew one of the SPs?
People rightly complain about CS all the time. It's mostly a garbage waste of time for US students. However, that's because US medical schools are good at identifying clinical skills weaknesses and fixing them before graduating students. Even so, a few students may fall through the cracks and for all its faults, CS does a good job at identifying them.
I think that if you failed the CIS section, you have some serious communications deficits that need to be fixed. It's not because you graded an SP's homework in high school. I don't know if you have planned to retake it, or have time to before starting a program, or can still match, or whatever. I wish you the best of luck and can assure you that whatever's wrong can be fixed.