I just had my XG3 installed in P5 (the knife-blade part of the hand, side of the palm below the pinkie finger) two days ago It’s flush with my skin. I might be able to tell its there if I look closely, especially with the installation wound still healing. I told my installer that I didn’t want it bumping out, and he said that in his experience, final results depend on each individual body. (Other folks here may argue with this point. I’m merely relating what he told me.)
In any case, I had the same concern and am happy to report that it’s not an issue.