In California, the practice of medicine is governed by the Medical Board of California.
The Medical Board states unequivocally that "physicians may inject Botox, or they may direct registered nurse, licensed vocational nurses, or physician assistants to perform the injection under their supervision. No unlicensed persons, such as medical assistants, may inject Botox."
The Medical Board also states that "Physicians may use lasers or intense pulsed light devices. In additional, physician assistants and registered nurses (not licensed vocational nurses) may perform these treatments under a physician's supervision. Unlicensed medical assistants, licensed vocational nurses, cosmetologists, electrologists, or estheticians may not legally perform these treatments under any circumstance, nor may registered nurses or physician assistants perform them independenly, without supervision."
Thus, the bottom line is that it is illegal for dental hygienists to perform Botox injections or to administer laser or intense pulsed light treatments in California. The laws vary from state to state.
Why do these rules exist? For the sake of patient safety. Botox injections may seem simple, but Botox is actually a very powerful medicine that can cause complications if not administered properly. I would personally choose an MD with expertise in facial anatomy (such as a plastic surgeon or dermatologist) to perform Botox injections.