If you had a "fit" in an exam what would happen?

During my maths exam this morning i felt as if i had a "fit" Although i didn't have an actual fit as i have dis-responsive epilepsy and I only black out. It is hard to tell that im in a "blackout" as i don't go limp or shake, i have felt tensed up before but i would do nothing that would make the examiners think there was a problem. All i know is that after my "blackouts" i feel confused as i don't know what has happened. normally if a teacher is talking and i "blackout" i notice as they would be talking through one thing and skip to something 3 pages later for example, but in the exam it was hard to realise. all i know is i wasn't struggling and i didn't feel like i spent more than 5 minutes on a question yet i still missed half the paper out. all i would like to know is if there is anything that could happen, like my mock being sent off instead?