I need to create an image of a person pressing their face into a piece of fabric. I think I can do it with a lighting effect or displacement map, but I’m not sure what source images I should be looking for.
You can probably get a reasonable approximation of the distortion using a spherical map; it will spread out things close to the center more than things along the edges, so center it on the nose or closest point to you. You can then add a partially opaque textured layer (try the “Render Fibers” filter) for the cloth. Shadows are probably easiest to add by hand, but you could try an “emboss” on the combined result of the other two.
How accurate do you need to be? Enough to fool a kidnap victim’s family, or just a stylization? 
The problem is that you need to take the RGB data of the image of the face… and use that to create the heightmap which could then be applied to a texture. While there might be a way to approximate it (I’m by no means a Photoshop expert), I’d use CrazyBumpto do it.
Crazybump builds bump maps out of regular photos, and a lot of my coworkers swear by it.