What is Brow Henna? Brow Henna powder comes from a plant. I mix some drops of mineral water into the powder to make a liquid. This is painted onto the skin and hair 3 times and then left to dry. It’s dries very hard and crusty which is quite different to a regular eyebrow tint. The #browhenna is left on for 10-20 minutes and then taken off with a wet cotton ball. The initial colour is darker and will settle over the next 24 hours. The after care is to not cleanse the brows area, steer clear of chlorine water. Anything that is stripping on the skin for as long as you can. If the brows are cleansed the colour may come off the skin but the colour will remain on the hair for longer than the eyebrow tint.