I had Radiesse injected into the backs of my hands to make the veins there less prominent. One syringe per hand was used. The injections weren't painful but the subsequent swelling certainly was! My hands puffed up to twice their size, looking like mitts and the stiffness was terrible, every movement of my hands was painful.
That level of swelling lasted a full two weeks. Once the swelling wore off, my veins looked nearly as prominent as before Radiesse and a couple of months later, I still have a small degree of stiffness in both hands but it is nowhere near what it was.
I think people should be warned that injections into the hands DO have these potential side effects, plus in my opinion, 1 syringe per hand is not enough product to camoflage protruding veins, it just added a degree of volume but one would need 2 syringes per hand to disguise large, raised veins in my opinion. I am convinced it is the prohibitive cost of Radiesse that prompts the "1 syringe per hand is enough" from providers. Few people would be willing to start out with a total of 4 syringes.
Despite the long-lasting discomfort endured post-injection, I am considering getting another syringe injected into each hand as the symptoms did eventually abate and now I have no discomfort most of the time - just a bit of residual stiffness/achiness but not enough to be bothersome.