I would wait
If there is a chance of gaining weight, you should wait until you have recovered from your thryoidectomy and check your appearance. Everyone is different, but in general a modest weight gain will be favorable for your facial appearance. At that point you might be able to treat any remaining areas of volume loss with less filler than you would have needed otherwise.
Do you want to have cosmetic procedure just before thyroid surgery?
I would not . You can have the voluma XC after you are finished with your medical ( non cosmetic ) procedures. There are a couple of reasons for waiting. Since the medical procedure is higher up on the list of your concerns, or it should be, then do it first. Voluma is a very quick office injection that takes a very short time. Your thyroid surgery is a bigger deal, requiring general anesthesia and perhaps an overnight stay in the hospital. Hopefully everything will go smoothly and you will be free to see your dermatologist or plastic surgeon in no time! If your concern is the eye area, they may or may not use Voluma OR they might decide that Belatero is the product you need. Let the expert decide this....
Beverly Johnson, MD
When should I get Voluma
A bit hard to answer, but in general, even people who gain weight still like definition in their faces so many still get fillers done. Voluma should be injected into the upper cheek area, and not specifically the tear trough area, but creating volume and definition in the upper cheek area often resolves the hollowness of the tear troughs.
"This answer has been solicited without seeing this patient and
cannot be held as true medical advice, but only opinion. Seek in-person
treatment with a trained medical professional for appropriate care."
Voluma should not be placed in the "hollow" of the eyes...it is a deep placement and specific for the cheekbone malar area. I would suggest discussing with a Board Certified Dermatologist with expertise with Voluma.