Playing with Photoshop today...

So I originally had two separate faces and decided to put them together, this is how...

 I used the shift key to select all of the layers on the second face to transfer. Once I had transferred the second face I then created a separate group for the layers for easy editing. 

To change selected areas to different colours I used the 'Quick selection tool' to select the area and then Ctrl B to bring up the colour options.

This was the original creation.

I then had a play with creating colour layers for the background...

So after all of the experimenting with the different background colours and ideas, this is my finished work (my favourite)...