Why have you only replaced the facial part? I'd suggest finding some nice golden ornamental textures and patching together the rest as well. Looks a bit poor with those low res paintings around the face.
I would, I want too, but it's hard to find good source pics for the texture, since every aspect of his mask is so specific, and I don't even have a camera to take my own source pics right now, not that I'd even know where to look anyways.
I find myself preferring your original eyes/eyebrows for the mask to the new ones-- his eyes look painted on, which is kinda jarring compared to the realism of the lips/nose. And I agree, if you can work more detail into the "frame", or whatever you want to call it, of the mask, I think that'd be good as well.
EDIT: Also, since his chin is so freakishly huge, it might not be so bad to give the mask the impression of some facial hair like a goatee.
I didn't like the eyes I had put on previously, they looked too different from the originals, and plus, I like his triangular shaped eyes. I could probably improve the edges around them more, but as I said, finding source pics is annoying.
A beard? Err, I don't think that would be appropriate, it's a MASK after all, I would probably think he'd have a beard under there though.