You'll want to start with the masks from your textures folder, such as 'cbodyshade.JPEG' , 'fbodyshade.JPEG' and so on. On a separate layer you'll have your UV lines (found in the 'references' folder).
Here's a quick and basic idea for the stripes on the bum and legs:
It'll look like this in-game:
As for the face, same principle:
Realistic scars are rather time consuming if you want a lot of them, but I suggest looking up makeup tip sites to get the general idea for colours and textures. Perhaps even looking online for various types of injuries (if you're not too squeamish, I am so I use the makeup tut ones). Remember- practice makes perfect, and never get mad at yourself. Hope it helps, hun!