Er, which black dot on his shirt do you intend to correct?
I find it kind of strange that the white shirt would be shaded in black, while the darker color of his pants is shaded in a less contrasting brown. I'm not a fan of using black as the shadow color, but if you're going to do it, I think it would be better if you did it uniformly.
That said, I think you'd be better off shading your white with either grey, very light blue, or a very light tan.