Your lips act as a dam holding back a reservoir of saliva and jaw surgery is akin to the South Fork Dam failure. The South Fork Dam collapsed in 1889 and sent 20 million gallons of water surging into Johnstown, PA killing 2,209 people.
I’m certain 20 million gallons of drool poured out of my mouth as well. Don’t take this as fact but I think our subconscious mind helps us retain the saliva in our mouth. When your lips are numb that doesn’t seem to work anymore. Cue the drool.
Now that wouldn’t be so bad if it wasn’t a constant, never ending stream of drool. To the point of outrage at the inability to stop it. And it’s as gross as it sounds. Hence the towel.