As long as you don't let more then 20 mA go threw it . You only need 2 volts to make it light up nothing else if it's a 2 volts forward
drop.
Don't play with really high voltage a red led can blow up and it could hurt you the case can pop off and sharp pieces hit you i know because i was messing with a current source and didn't set it to it's lowest setting if i had not had glasses on it would of got my eye it broke the glass plus i had to dig some of it out of me.