So it has been 6 days since I got my Monroe piercing done. Help?

Ok so my question is what size can I order for the bar? I realized I shouldn't be changing the labret at all since it's not fully healed but it fell out so I experimented with a 5/16 I think? And it was way too small and hurt. I want to order some labrets online for when I can change my piercing after it heals but I don't know what size of bar to get? What is a two or three sizes bigger than a 5/16? Or more? I don't know anything about the sizes! I want a long bar but not to long of a bar. A just right bar haha.