Botox and other cosmetic treatments can be found in many places, some of which range from reputable to non reputable places. As a board certified dermatologist I have seen many issues including serious, long term problems when these procedures were performed the wrong way. While a pharmacy is a great place to pick up a prescription, I would NEVER trust something like my face to a person who dabbles in cosmetics. It simply isn't worth the risk. Even if it is a huge savings in costs, the negatives greatly outweigh the positives..
In the United States, each state has their own laws that determine who can perform injections of Botox and fillers. I am not aware of any state that would allow a pharmacist to administer a Botox injection. It is possible that a pharmacy might have a doctor or nurse on staff that could perform a Botox injection, if it were legal to do so in that state. My recommendation would be to have your Botox treatment performed by a physician in his or her office.