They say filler dissolves over time, but I'm sure that's not the case. At the time, it was applied to my forehead and front cheeks, and they're all still left on my forehead and front cheeks! Of course, there are some that disappear, but there seem to be some that remain. There was no problem until the 2nd or 3rd year, but as I got older and time passed, the problem with filler is that the areas that fall out are removed and the areas that do not fall out are not. However, it is not a big problem yet. It's long, but I plan on retouching it sometime soon.