Certainly fillers are done for the top of hands to hide veins. Doctors have used fat injections, and products such as: hyaluronic acids such as Restylane and Juvederm, and Radiesse (these are not FDA approved uses for these products). There is a concern that there will be more voluminous and long term swelling in the feet than in the hands and there may be a greater chance of infection. If you are thinking of having this done, make certain that your doctor has done this many times in the feet otherwise, you can’t know what to expect as the results might be quite different than in the hands. Furthermore, there might be trouble in wearing shoes for weeks after the filler is injected.