No-no-no! I actually prefer GIMP. I'm just asking so I know how to help. Right-click the bottom layer, select "Duplicate Layer". When you've done, go to "Layer", then "Transparency" and click "Add Alpha Channel". What that does it make it so that when you cut bits out of the layer, the gap left behind will show the layer beneath it. If you didn't do this, it'd just show white. Next, click "Colors" at the top, then "Colorize". Play with it until you've found a color you like. Hit OK. Use the selection tools to select parts of the newly-coloured layer, then hit "Ctrl+X" to cut them (or click "Edit" then "Cut".) Only do this for bits you don't want to have been coloured. E.g. Perhaps the eyes, or teeth. Done, new skin color!