Can Sculptra be injected in a site where Bellafill has been injected?

Yes fillers can be layered if done by an expert.  I suggest seeing a physician trained in facial sculpting who uses a lot of fillers for shaping and lifting of the face.  Best, Dr. Emer. 

In my opinion, it is okay to inject Sculptra into an area where Bellafill has previously been used.  I would recommend waiting at least two months after the Bellafill injection before adding any Sculptra to the area however.  The other option would be to just use more Bellafill instead of Sculptra.  

In general, different fillers can be injected in the same area if using US FDA approved fillers. It should be no problem what you propose to do and some of my colleagues to this routinely so you get more global volumization with some immediate long lasting improvement as well.

Bellafill can be used in conjunction with other fillers,
however any other filler will not be as natural nor will it have the longevity
that Bellafill has.

I hope that helps.

Best regards.