My 3 favorite skin supplements

Coenzyme Q10: A fantastic anti-oxidant that protects against oxidative stress and gives cells the energy they need to repair." May also play a role in treating skin cancer. Make sure to take in AM since it can be as stimulating as caffeine.
Fish or Flaxseed oil: Omega-3 fatty acids strengthen the skins barrier, which keeps moisture in and irritants out. Also help reduce inflammation and treat skin conditions such as eczema.
Info from this April 2010 Allure