This is a more complete version of a retouch I did for my X-rite webinar on retouching. The basic approach is Frequency Separation to place texture and color/tone in separate layers. This allows you to re-shade the image while leaving the texture intact. I have to thank Doug Pizac for this wonderful portrait!
Mac only: If you're going to warble along with your favorite song, make sure you get the words right. Get Lyrical is a free app that automatically displays the lyrics of whatever song is playing in iTunes.