I've read stories of people having this procedure done and look worse after initial results wear off. Can at-home HIFU generate enough heat to melt fat or cause atrophy? Is it possible to reach SMAS layer with frequencies of 10MHz, 7 MHz or 4MHz, to cause a skin tightening effect, and leave the subcutaneous fat unaffected? I know depth and temperature are both important. At what temperature or frequency does subcutaneous fat start to be affected? What temp or frequency is safe for at-home use?