I would appreciate guidance in this matter if anyone has any to offer. I am very new to 3D Painting in Photoshop but I am nominally knowledgeable of Photoshop in general for 2D work.

I exported Genesis to an .obj file and painted on it in Photoshop 5.5.

When I paint on his face, other marks show up on his torso and thigh and eyes, even.

It is like all of the diffuse maps are "stacked upon one another" (though not in layers.)

If anyone has experienced this or knows a good solution or tutorial about this, please share that info here.

Genesis like V4 and others have multiple maps. The only way to texture properly in Photoshop 5.5. you would have to have a character with one map. 

I would love to know a work round to that issue but haven't found it yet.. My favorite program to texture DAZ characters is Deep Paint 3d, you can texture on multiple layers
and use Photoshop together. They aren't updating Deep Paint 3D any more but still it's worth it for all of DAZ characters.

Hope I've helped...

Stormi 

"The best and most beautiful thing in life cannot be seen, not touched, but are felt in the heart."
                                                                                                         

• Helen Keller

Can it still be purchased?