Do you have to wait until filler wears off completely before repeating it?
No, in fact I think it’s better to schedule your next treatment prior to it’s complete resolution. If you do that, you’ll gradually build more of a base and your results will keep improving. Fillers often begin to last slightly longer over time. Could there be some slight natural collagen induction just from the needle? Hard to prove.
A common scenario in our office is to schedule the first Juvederm follow up appointment at 4 months, then go 4 1/2 or 5 months and then even a little longer like 6-9 months. This depends somewhat on your age and particular anatomy. The older you are the more frequent treatments you are likely to need. Here is my article on Fillers in Depth so you can learn more about them. Hope this helps! Dr. I