How to get rid of the numbness from your mouth after the dentist so you can eat lunch without drooling?

Time. There's not much i know of to speed up getting your sensation back after an injection. Maybe you can try having a shake for lunch?
Oraverse. Oraverse( phentolamine mesylate) is an anesthetic reversal agent. It is a relativly new product on the market which speeds the process to help numbness wear away much faster. You can ask your dentist if it something that they offer, another thing you can try is drinking warm liquids which may help dilate the local blood vessels and shorten the duration of the numb feeling.
Oraverse. You can request a fairly new product called oraverse. Because it is new it is a little pricey, compared to anesthetic. If you would like it, your dentist may ask you to pay an extra $10 to $20.