What layer of the skin/tissue is best to place restylane/juvederm to avoid the filler from moving around?

This is difficult to answer without pictures and will be based on your anatomy and desired results. Well-placed filler shouldn't migrate. I'm not sure when you had your injections. It can take 1-2 weeks for final results. If you're unhappy, you can have it reversed with hyaluronidase and try a different technique next time. See an expert. Best, Dr. Emer

One of the nice attributes of Voluma is how soft a result it achieves.  This requires that the filler have a degree of horizontal diffusion to blend its effect.  It might not, however, be the best filler for you to achieve your desired results.  In my hands I have that Restylane Lyft tends to produce a more focused result with less lateral spread, and also can have excellent longevity. 

Thank you for sharing your question and I am sorry that your results have not been what you anticipated.  Because of its thick gel nature I place Voluma just above the jaw bone for chin augmentation.  This limits the risk of bruising but also decreases the possibility of filler migration.  If you did not obtain the look you were after I would discuss this with your injector so that it can be revised.  Hope this helps.