The skin on your face is much thinner than the skin on other areas of your body, particularly your legs, which is why body makeup is thicker than face makeup. If you want the best coverage for flawless looking legs, it's important to use the right makeup. While there are brands that make one makeup for "body and face," you probably won't get the coverage for your legs from a makeup made just for faces.
After you've prepped your skin and applied a primer, it's time for the makeup. Most body makeup is cream based. You should treat this just like a foundation for your face. There are also a few brands that make an airbrush body makeup that you simply spray on.
If the cream or aerosol base doesn't offer the amount of coverage you were hoping for, you can apply a concealer with a brush next. The brush and amount of concealer should be equal to what you want to cover. Try to put the concealer just on the imperfection and then feather it out away from the blemish with the brush to blend.