there is nothing to fear, ive done it, several times, what happens is the doctor sprays the liquid on the lip and it tingles, you feel a slight burn, and that is it. Then the area bubbles like a blister an hour later and the blister pops and it is fresh raw skin underneath that scabs like a real cut and heals, only mine mine healed until it hit the affected area meaning the unaffected area healed back to normal and the affected area it stopped and the scab fell off and it went back to peeling.
Like I also said, ask about the cauterizations with the heat laser, much more effective and helped significantly. it reduces my top area by fifty percent. too bad my derm retired or id do it every month till nothing else could be done.