Before we address the Radiesse question, I do not recommend silicone in the lips. Silicone is supposed to be an inert substance, but in fact can cause great inflammation and granuloma formation after injection. It may not be evident at first, but may happen years later. Silicone does not dissolve. It is permanent, and removing it is a surgical procedure.
It is much safer to use a hyaluronic acid filler, like Restylane or Juvederm. The soft tissues surrounding the lips, like the area of the chin and the upper lip above the vermilion (the red area) can be revolumized with Radiesse or Sculptra, which will make the lips themselves look better too. One of the reasons the lips appear thin with aging is the loss of volume in the surrounding areas with really what amounts to descent of the area between the nose and the lip.
As far as Radiesse is concerned, there are a number of reasons why the cheeks may be red or flushed. If a topical anesthetic was applied before the procedure, you may have had an allergic reaction to it, or the skin may have been irritated by vigorous cleaning with alcohol. If you iced the area aggressively after the injections, there may even be an ice burn.
Radiesse is usually injected deeply, down to the level of right above the bone to give volume and lift. It may have been injected too superficially or there may still be residual swelling after the procedure.
Although 4 syringes seems like too much, sometimes when there is severe volume loss, that may be required, albeit rarely. I usually start with one syringe per side and see how things go. One can always add more later.
I do not recommend adding more Radiesse at this time. Wait 2-3 weeks and see how things look when all the swelling and irritation settle. Also, consider getting a second opinion from a board-certified dermatologist or plastic surgeon with training and experience in injectables.