Exams?

Depends on what the exam is for. If its to have a career maybe you should re-evaluate what you want to do with your life if you cannot make the test failure important maybe the job wont be a good fit for you. I had the same problem with my old major.

It's for science... I don't want my career to be anything to do with science anyway but I'm just scared that it's going to be on my CV for like the rest of my life that I've failed it.

CVs count more for experience in the long-run. While exam results may have some influence when you are looking at uni or first looking for work after education, it won't be long into your career-life before it will have little impact, especially as it isn't the field you want to be in. That said, it can't hurt to get the best grades you're capable of while you have the chance whether you care about it or not.