Does a med spa in Hawaii need a medical director?

Short answer
Not directly — no cited rule requires a med spa to name a medical director, and Hawaii licenses no med spa facility; but diagnosing or treating is the practice of medicine, so each service must sit within a licensee's scope or permitted supervision.

Hawaii defines the practice of medicine by any means, method, or agent, and the sections cited here put the supervision line in the statute rather than in a rule about medical assistants. The practice of medicine includes the use of drugs, surgery, electricity, telehealth, and any means to diagnose, treat, prescribe for, or correct any human condition, and no person may practice or offer to practice medicine without a license from the Hawaii medical board. A physician assistant or emergency medical services licensee may render services under the direction and control of a licensed physician, that direction and control does not in every case require the physician’s personal presence, and the employing physician retains full professional and personal responsibility for any act that constitutes the practice of medicine. Anyone practicing medicine under a physician’s supervision must be licensed as a physician assistant, except a person trained to do only a very limited number of diagnostic or therapeutic procedures under a physician’s direction, who is not deemed a practitioner of medicine; the board sets the degree of supervision, and a physician who supervises below it commits professional misconduct. The Board’s rule makes the physician assistant the supervising physician’s agent. A registered nurse may delegate nursing tasks to unlicensed assistive personnel but never assessment, evaluation, or nursing judgment. On the cosmetology side, an esthetician is defined by the work of massaging, cleansing, stimulating, manipulating, exercising, or beautifying the skin with hands or nonmedically prescribed apparatus, cosmetic preparations, and hair removal by means other than electrolysis; the practice of cosmetology is beauty care of the skin, hair, scalp, and nails for cosmetic purposes; and the chapter does not restrict licensed professionals acting within their own scope. None of the sections cited here names microneedling, lasers, or a medical director.