Should I tell my teacher my paper was correct if it means my friend will lose her point?

Got my exam results in class today and I went up to my teacher to see what I had gotten wrong. I checked my paper and asked what part of my paper was wrong, and she told me to check it with my friends paper, if mines right then my friend will lose her grade (???)

I look over the question and ask why my friend’s is -1, and suddenly it dawns on her rhat she had it wrong she pulls me aside and makes me put the paper back.

So…