Thank you for your question. Yes, you may still have fillers layered in on top of your implants. Having implants never precludes you from having some type of filler. I do strongly recommend you go to an expert injector though.
Yes, we frequently place fillers in the cheeks to aesthetically shape them when Cheek Implants have been done elsewhere. There's no reason to remove previously placed Cheek Implants if they are contributing some (but not all) of the ideal aesthetic size and shape to the cheek...and the patient does not mind having fillers (I prefer using Perlane) to the area about once a year or so. Fillers, to the Cheeks, are quite safe, in the presence of Cheek Implants as the filler is placed in the subcutaneous fat layer while the implants sit directly on top of the cheek bone at a much deeper layer.