First though, let's apply some brushstrokes to the underneath layer so that it looks like these features have been painted. Notice now that we have lost some really important detail from his face, notably the sparkle in his eyes. We will bring that back in a bit. Ctrl-s to save. The white parts of your mask are the parts that you cannot see through to the layer below.
Black parts are transparent to the layer below.
Grab your paintbrush and paint around on this mask with black. Choose your linear gradient tool and drag a gradient across the mask. Before you go back to the directions, fill your mask back up with white. Ok now click the mask in the layers palette to be sure you are working on it. Then, using a fine feathered brush, draw in black on the mask around Michael's glasses, eyes, his mouth edges, and his nose contour lines.