Personal experience....been there did that type shit and has seen a friend do it. I'm sure others may have other opinions but these are my own.

Harm to the plant.......never seen any type of harm due to lopping one top.

Getting stoned in a few hours? Unlikely....that would mean an oven or micro dry and you wreck the taste and the buzz isn't what it should be if anything. I've taken a small bud from the lower half and let it sit out for a day in a dark place.....not bad but it so much more potential.

If you can score tomarrow I'd just wait it off. The biggest temptation is to give the ol' "test try" and you basically do nothing more than taking a delicious bud and turning into shit....just wait off and that bud will show it's appreciation to ya in the future.:thumbsup:

Have a good grow!:jointsmile: