@Scalessayeek @Choux @Chucklesisters @Thebaldprimadonna and others - I too am in the saggy, flappy skin club, but I can confirm that, while it may not disappear, it definitely does improve.
I am now 1 year+ in my MJ journey (first dose was on 12 Jan) and the saggy bits on my arms and on my neck are improving. I do Pilates twice a week and some yoga and lots of walking, and my skin is definitely better. My bum and my tummy still look strange, but my arms and my neck have contracted somewhat and I hope it continues. I am working on it, anyway.
Still losing, albeit slowly, and my measurements continue to improve too. However, I am on 12.5 and I do find that I am getting hungry by the end of a dose. I really need to focus on bulking up my portions with nice fruit and veg to fight that. And continue to drink my water, which has been a challenge from day 1.