Corset platysmaplasty for skin laxity? 40F, 124lbs, 5'6 (Photos)

This skin laxity appeared over night, I think precipitated by masseter botox I got on my left jaw for bruxism. I have tried botox at but don't think its working. I have been told a corset platysmaplasty is the solution but I don't see very strong platysma muscles pulling, its more skin sag from my submentum or jawline, although I dont have significant jowls and my jawline is well defined. My neck looks good overall. How shall I treat this? Im 5'6", 124lbs