If I had an allergic reaction o Sculptra, how likely to have one to Voluma?

In my experience, allergic reactions to Sculptra are extremely rare. That being said, Sculptra consist of poly-L-lactic acid while Juvederm and Restylane are made of hyaluronic acid. Since you have had Juvederm in the past without issue, I suspect you will not have an allergy to Voluma especially since allergies to HA fillers are rare to begin with. I prefer to use Restylane Lyft over Juvederm Voluma when treating the cheeks. In general, I prefer the Restylane family of fillers over anything using Allergan's vycross technology. 

I doubt very much that you had an allergic reaction to Sculptra. Most likely the problems were secondary to the technique that was used or insufficient dilution of the product. Regardless, you can easily have Voluma used on your face just make sure you go to a plastic surgeon who is well-versed with a the is of volumetrics. Good luck from New York City