Start by opening an image of man.
1. Isolating the area
Create selection of the man using polygon lasso tool. Press Ctrl+J to copy paste the selection in a new layer. Hide the layer.
Select clone stamp tool and clone the edges of the face as shown in the image below.
Unhide the man layer. Create a smooth selection using polygon lasso tool.
Press Ctrl+Shift+I to inverse the selection. Press Delete.
2. Hair today, gone tomorrow
Select healing brush tool. Press Alt and click on skin area to define the source pixels. Now click on scalp area covered with hair to change it to a bald patch.
Select sharpen tool and and apply it over the head areas.
3. Creating a realistic shade & texture on scalp
Create another selection as shown. Create a new layer and fill it with skin color. Move this layer right below the man's cutout layer in layer order in layer palette.
From "Filter" menu select "Noise>>Add Noise". Apply settings as shown.
4. Time to shine
Create a new layer. Select a big feathered brush tool with white as foreground color. Click once to create head shining.