Skin change?

[Darkholme]

I'm trying to make alleria from warcraft II. of course she looks remarkably like sylvanus, so I'm keeping the model. What I can't figure out, is how to I make the model of her face keep the original skin on one side, and instead of flipping it for the other side, call on another texture which I dres for that side. she has a stripe-thing across her face on an angle, so I can't have the skin being completely symmetrical.

Can anyone help me?