If you go to a costume store you can find a type of wax/gum that is used specifically for covering eyebrows. I believe Ben Nye makes some...the stuff I'm talking about is usually called Spirit Gum or Eyebrow Sealing Wax. Just make sure you don't put it on TOO thick or you'll have like, a Neanderthal brow thing going on. I've seen it. It's not pretty. You actually don't need a whole lot to cover them up though. If you get the Spirit Gum, get either the water soluble stuff or also buy a remover...or else it'll be a nightmare to get off.