How do you edit a mat to change like eyeliner color or mascara color...do you have to paint the base mat...is there some kind of overlay guide that shows where to paint the color...I am not good at texturing so I am trying to find a easy way to do it

No easy cheat to accomplish it, unfortunately. You'll either have to do some painting yourself, or download/purchase a set of ready-made makeup layers that you can overlay onto your base texture in a paint program.

Yes, overlay guides are available. They're usually called UV templates or seam guides. Snowsultan is particularly well-known for these, but you can make your own if you have some familiarity with UVMapper. For which figure do you need them?

It's possible to blend two textures together within Poser 5's material room, so if you're running that software, you can achieve the overlay without altering the base texture. Mason recently posted some examples of the technique.