If you are only doing the upper lip this should be no problem. Any dentist can do a "nerve block" that will numb the lip (but not the sides of the lip very well ... not too painful there).
The only potential problem is that you might want more work than is safe. The numbed upper lip is probably the number one area where clients/electrologists get in trouble ... by being too aggressive.
Have the treatment and then wait a couple months for the follow-up ... do not work longer than your electrologist recommends for a "non-numb" upper lip. (The anesthetic also masks all signs of overtreatment ... so this is a nasty risk.)
You won't feel the injection at all (area is pr-enumbed with gel) ... ZERO! Depending on what is used, you can expect 1.25 hours (the usual 2% Lido WITH epi) to much longer (Marcaine with epi). Just tell the dentist how long you want the numbness to last.
the dentist is not gonna just numb me for the hell of it! i'd need a dental-related reason, would i not? what non-extreme dental procedures do they numb you for?
i've already booked my appointment with the place in dallas, anyway and i've booked my flight, but if i need another round, the above questions i just asked would be useful to know.
what are the risks if over-treated?