I personally perform TempSure Envi treatments for skin rejuvenation of the face.  I have also had TempSure Envi performed on my face by my staff.  I find that any discomfort occurs mainly due to the operator/technician being distracted, trying to do two things at the same time or talking to someone else in the room and that sort of thing.  For example if the operator holds the device while it is "on" in one place instead of continuously moving it while reaching to get some additional gel (needed to help the device glide smoothly and transmit the RF signal through the skin), then a "hot spot" could develop.