a boycott with an end date picked in advance is not a boycott. It's a pause.
ONE DAY OF LOST SALES IS NOTHING. That could happen if their machines go down for a day (which does happen, btw)
Seriously, none of the businesses that you need to feel any pain won't feel any pain with a one day boycott. All they have to do is sell better the day before and after, and your boycott is erased.
A successful boycott takes weeks or months to be effective. It's starvation, and you can't speed that up.