The Botox party looks like marketing genius: gather a host's friends, make it social and fun, treat a roomful of patients in an evening, and let everyone leave delighted and referring. It is effective marketing. It's also one of the cleaner ways a practice walks into a compliance trap, because the very things that make it a great party — the social atmosphere, the casual setting, the volume, the occasional glass of wine — are in direct tension with the individualized medical care each patient is supposed to receive. The format isn't automatically illegal, but it makes the requirements hard to meet, and "hard to meet" in a roomful of patients is exactly where exposure lives.
This is general education for owners, not legal advice. Confirm group-event compliance with counsel and your medical director.