started off with 2 images for this, one of my face and one of my hands covering the face.
I then opened both images in camera raw and applied the same settings to both photos.
Next i aligned the photo of my face with the one of my hands.
Then it was just a matter of masking and blending the images together.
This took a few attempts to get it to blend well, but I am happy with the end result.
total time was about 4 hours