I began with a random model shot I found on Google images. I was looking for something with decent resolution and lighting that would serve as an ideal starting point.

The next step was to add a sense of surreal symmetry to the photo. I used the marquee tool to copy and paste half of the face as a new layer, and then transformed it horizontally to obtain the effect. I next use the dodge and burn tools to superimpose new shadows and highlights so that the lighting still seemed natural.

Next I duplicated the layer and applied the gaussian blur filter to it. Then, I made a layer mask over the blurred layer. In the mask, I used a black radial gradient to delete the blur around the face, smoothly blending a frame of blur with the main features of the face.

Next I selected one of the irises, and utilized adjustment layers to manipulate the natural color. When I was satisfied with one eye, I duplicated it, transformed it horizontally, and translated it over to the other eye.

Next I added the first object that I planned to blend into the face. At this point it is clear that the face and horn are two separate objects, but I just wanted to get it into place.

This picture is the result of some procedural experimentation. I messed with the face's curves, applied some new objects, created a new brush preset from a image of cracked earth that I found, and also liquified part of the face.

Next I decided to change the saturation of the skin so that it would blend better with the horns. I also decided to change the color of the eyes.

The next step largely consisted of finishing the scheme of the horns' placement. I also did a little bit of blending between the horns and face.

I added two new overlaying layers to tie the image together.

Using the burn tool, I added some shadows to the horns to really solidify the horns as extensions of the face.

The last step was to blend any details I missed.

That's all, thanks for giving this a look!