Sculptra left my face fat, would Thermage be a good way to reduce the fullness?

Thermage is a radiofrequency based treatment for skin tightening. It does smooth the skin and increase collagen production which gives the face a lifted appearance. That being said, it is hard to comment on your specific case without seeing a photo or evaluating you in person. My recommendation is that if you are considering Thermage, make sure you understand what is is for and make sure that you get treated by the 3rd or 4th generation of the device (Thermage CPT or Thermage FLX) both which are quicker, more effective, and comfortable than earlier generations of the device. I am a big fan of Thermage and believe that is is the cornerstore of any nonsurgical skin tightening treatment. 

Hello,Sculptra®️ (Galderma, Lausanne, Switzerland) is a filler containing polylactic acid. Polylactic acid-PLLA is a synthetic polymer from the alpha hydroxy acid family. It is used in the form of an injectable hydrocolloid suspension. PLLA microparticles have a diameter of 40-63 μm. PLLA particles cannot be phagocytized by dermal macrophages and cannot cross the capillary wall in the tissue. As a result, PLLA particles remain in the tissue for a very long time until they are metabolized. Thermage CPT or Thermage FLX is the first choice for non-surgical facial lifting worldwide and is FDA approved. Thermage does not have the ability to break down fat cells.For alleviating the feeling of fullness in your face, I would recommend Ulthera to you. While Sculptra has created a facial lifting effect, if the fullness it provides feels excessive, using focus ultrasound with a deeper wavelength would be a more appropriate option. Ulthera both increases lifting and thins deep fat tissue. Ulthera will make you happy.
I hope this helps!

Thermage can tighten and smooth skin but will not reduce fullness.  Strategically placed filler may make your face look slimmer.  Consult an experienced cosmetic dermatologist or plastic surgeon.