Skin Color Incorrect for Tattoos

Could someone help me? I'm entirely new to creating custom content for the game, and I've been having an issue in my game where the tattooes that I've created will show up, but the skin colors of my sims are off even when I use the default body textures. For instance, the skin will be very, very white no matter what skin tone I select in the game, even though the tattoo itself looks fine. Is there something obvious that I'm missing? I'm using Paint.net, not Photoshop, but I've been saving my dds files as DXT5 and have the program set to "generate mip maps." 

I'm having difficulty figuring out how to upload a picture, but my sim's skin looks really, really white, even though the tattoo looks perfect. 

I've read as many tutorials on the topic as I can find, but can't find a solution...