Are you Italian? Based on your avatar picture (beard shadow and the fur coming up out of your shirt [woof]), it looks like your Sly shadow is there to stay for a while. I had the same situation early in my Sly years, but as I age...most of my pepper is turning to salt. My sly shadow is diminishing as well. Just be patient and your shadow should start to go away.
i think it depends and how you shave your head too. I have dark brown hair but when I'm shaven i have no shadow. just massage the cream or gel into your scalp and take your time, should help minimize shadow