Used to sleep with a piece of clear scotch tape between my eyebrows to prevent a furrow from forming overnight.
If your dermatologist knows what he/she is doing, you will have no new wrinkles in the treated area. Also, don't overdo it. While I have had no adverse reactions, e.g., droopy eyelids, some people have, so at first, do just a little, then build up with every appointment.
Worth every penny.