No, you would save it as a different map... What I would reccomend, is to load in the Displacement Map and the Texture Map both into Photoshop, with the Texture Map as the upper layer and the Displacement Map as the "Background. Next, I'd reduce the opacity of the Texture Map to about, oh, say 40% to 60%, whatever is clear enough to see through. Then, with a VERY LIGHT touch of the airbrush, on a new third layer, trace over the veins on the Displacement Map, fading them into the skin where the veins end. Then, make the "Texture" layer opaque once more, flatten the image, then save. It would go right where you have the existing texture map.

Remember, kids! Napalm is Nature's Toothpaste!