My cheek implant is too small on one side, can I just add another implant?

Thank you for the questions. If you have an asymmetric face (from asymmetric bone structure) the best option is likely placement of a larger implant, or a different implant shape, on the smaller side. Stacking implants is not a good idea, as these will inevitably shift over time. Removing and replacing an implant on one side is not a difficult procedure and could be performed relatively quickly. Alternatively, if your issues are relatively minor or are outside of the standard area for cheek implant placement, soft tissue fillers can be used around the implant. This would include Radiesse or Voluma for the cheekbone and temple areas. Best of luck moving forward!

In my opinion, you should never stack implants as they will not stay in place.  You didn't submit photos, so it is hard to give exact information, but if you are female, you should not have cheek implants that extend toward the temple as this will give you a wider face.  Feminine faces typically are fuller and rounder in the front.