In addition to the potential issue already mentioned with sterility, the other practical reason that Radiesse cannot be stored is that after a few days, the product becomes hard and is then impossible to inject. This is true whether it is mixed with lidocaine or not.
In answer to your question, it's not uncommon to place radiesse deeply, even at the level of the cheek bone. However, i think that the majority of your problem with volume is in the lower cheek area. This area needs a little rounding out to give the face a more youthful appearance...
Radiesse is calcium hydroxyapatite and can be injected directly onto bone. If you desire more volume correction, facial fat grafting should be considered. Kenneth Hughes, MD facial fat grafting Los Angeles, CA