Is ThermiTight used on the face permanent?

Nothing, including a facelift is permanent. Skin continues to age and sag eventually, but the improvement of tightening from ThermiTight puts the patient ahead on the aging curve so they will maintain the “years they gain” compared to not having the procedure. In other words, if two friends look similarly aged, and one receives ThermiTight and looks better by several years, that difference in their appearance will probably be maintained as they both age and look more droopy over time.
To guard against facial nerve damage, there is a nerve stimulator device that we map out the crucial anatomical location of the nerve prior to the procedure.