I totally get what you're saying about the lack of sleep during exam season. It's tough, but it's really important to get enough sleep, especially during times of stress.
Not getting enough sleep can definitely have some long-term risks, like heart disease, diabetes, and mood disorders. So, it's super important to try to get at least 7-8 hours of sleep each night. I know it's hard, but maybe try to create a relaxing bedtime routine, like reading or listening to calming music before bed.
If you're still having trouble sleeping, you might want to talk to your doctor to see if there's anything else you can do.