Why does a gum lift not last? (Photo)

I have had a gum lift twice, but both times it looks great at first and exactly what I want and then the gums just fall back down again and I go back to a gummy smile. Why is that? The first time I had it done with a laser and the second time I had the scalpel and suture approach because they said that would be more permanent. Any advice? I have also had lip lowering. There is no medical reason to have any sort of jaw surgery.