most people tend to say Nay, but I put in a full day, but make sure to get a good night sleep.
Review rote memorization stuff, aka criteria, weird factoids you jotted down from UWorld, toxidromes, and do about 100-200 questions, but don't kill yourself.
Eat good dinner, end night with something pleasurable (i watched a movie after my 7 pm dinner, and went to bed 10-11 pm).
Truth be told, I don't think the whole studying vs not studying is going to affect your score that much, unless you saved something for that last day (like with me, I saved Ethics and Biostats ha)
EDIT: But I definitely think doing 100-200 questions is a good idea just to get in the zone if u haven't been doing that much a day during your studying