Get rid of the comma after box.
The pronoun in the beginning of the second sentence has an unclear antecedent (the noun the pronoun belongs to). Change Press it to Press the button.
I recommend deleting to when you pressed it as unnecessary. Whether you keep that phrase or not, change the period before a year without consequences to a comma.
You have a box with a button. Press the button, and a year later you’ll be right back, a year without consequences.
(If this time-machine button box thing doesn’t also erase your memory of whatever you do during that year, there are still consequences for you, even if not for anyone else.)