Although this is available in one of the behind-the-scenes documentaries on the 'The Dark Knight Rises' bonus DVD, you may not have seen it. If you haven't seen it, you should check it out! In these photos, you can see how Bane's mask evolved over the development of the project. Another interesting photo is the one of Tom Hardy as Bane before they digitally removed all of his tattoos. It may not have made sense with the character, but the tattoos actually make him look even more menacing.
Take a look at the photos, then let us know what you think in the comments