Can I have submalar implants placed below my malar cheek implants?

In your case two options are available; replacement of the implants with larger and extended implants to cover for volume loss or fat grafting on top of the existing implants. In person consultation with a board certified plastic surgeon with good reputation in facial implants is recommended. Good luck.

While you can place submalar implants below your existing cheeks implants that is a potentially unstable situation since there may be little good tissue onto which the new implants can attach. It would be better to have one single implant per side. Unlike nearly two decades ago combined malar-submalar implants now exist that can augment both combined areas as a single implant. Thus removing your existing cheek implants and replacing them a broader surface style implant would be more stable with less risk.