Can I Have a Hyaluronic Acid Filler Put in over Radiesse in my Nasolabial Folds?

Filling the area with Restylane should be fine. I may recommend waiting a full two weeks after the Radiesse injection to make sure all swelling has gone down. Best of luck!

Waiting a full two weeks to let any swelling heal would be ideal. After that, there is no issue with having a HA filler injected to the area

It is definitely possible and not uncommon to place a hyaluronic acid filler, such as Restylane, over an area that has been previously treated with Radiesse.  There should be no problem with this approach.  

Not only is this possible but it can be used to create a more refined appearance. A thicker, heavier filler can provide volume and lift while a thinner, hyaluronic acid filler can be used to treat overlying finer lines. Seek an experienced physician injector (Plastic Surgeon or Dermatologist) for the highest probability of a great result. I hope this information is helpful.

Using a hyaluronic acid filler over Radiesse is a great way to fine tune results in the nasolabial fold. Each filler is slightly different, and you can optimize your results by using both. Since Restylane is dissolvable, it is safer to use in the upper cheek by the nose. There is a large blood vessel there (the angular artery), which is probably why your new injector avoided the area with Radiesse (not dissolvable).  Small amounts of Restylane injected slowly is a better bet in that area.