I would say the cost of a vial of medicine for neuromuscular spasms and dystonia (the initial purpose, not cosmetic) is cost prohibitive for a lot of people. Usually, insurance should cover it, but the cost is $1,000/vial for a medicine that was approved over 30 years ago, and the price has only gone up, not down. Some plans (off the top of my head, some Blue Shield plans and anyone who is on straight Medicare/Medicaid) won't cover the cost.
There are a couple of competitors that work roughly the same and are slightly cheaper but it def seems like an oligopoly to keep the costs artificially high.