Well really depends on how it actually looks like, but it is possible and they have to show it to other examiners if they can't . Otherwise, no marks or a few Benefit of Doubt marks
I'm going to assume you mean it's a form of cursive writing, and if that is true then most likely they will be able to read it. This is obviously assuming you're not an exceptional case.
I would suggest asking one of your teachers, they may be able to guide you better as they have an objective view of your writing.
I asked myself this too again and again. A year ago, I asked a teacher this question and he meant that in my case it is readable. And many people told me that my handwriting seems to be cryptic. 😑