Routine is more important than anything you may or may not do the night before an exam.
Think of it like a sporting event. Regular training, good diet, etc. You will NOT play well in the final unless you have been training well and regularly for the previous 6 months, with good diet and lots of rest.
Your 'final' is next June. Aim for that.
But, as a general rule, don't study later than 9.30/10.00. Be in bed by 10.30.