who can administer botox in the state of pennsylvania?

Every state governs the regulations of who can provide injections, and what supervision is necessary. I don't know the answer for PA but if you contact their medical board they may be able to tell you or direct you to the correct office. You want to make sure that whoever is injecting you is using aseptic technique, avoiding cross contamination between patients and is using an American FDA approved vial of Botox from Allergan.  Your best bet is to see a board certified dermatologist or plastic surgeon.

These treatments are regulated by the Medical Board of Pennsylvania.  Google them and you will find their website and their contact information.

I recommend you see only a board-certified physician (MD or DO) certfied by the American Board of Medical Specialities (not other boards) in one of the FOUR core cosmetic specialties with the full training to manage not only giving Botox, but also any complications that may arise. Those would be board-certified dermatologists, plastic surgeons, facial plastic surgeons (ENTs) and oculoplastic surgeons (Ophthos with extra surgical training). Botox seems deceivingly simple but when done wrong can be a disaster.