HIFU to slim down arms? Yay or Nay? (photos)

I was thinking of getting my arms slimmed down (a bit of “bingo wings”). I always assumed HIFU is a milder/gentler Ultherapy (MFU), but the more research I do, the more I find about many people complaining about life changing side effects such as NERVE DAMAGE, FAT/MUSCLE ATROPHY and continuous hallowing of the skin/area for the face. Are these side effects also true if you want to slim down/ apply it to your arms? Alternatively if anyone can recommend a better, more effective treatment. I’m all ears