You can prepare your own edible recipe for real latex FX makeup. The kind of makeup is most often used for getting the fake skin, scars and warts.
Mix tapioca flour with water in the ratio 6:1 and heat the mixture by continuously stirring it in a medium temperature. The tapioca flour dissolves in the water and gives the exact latex texture. Add blue food coloring and several squirts of liquid foundation to the latex mixture at a reduced temperature. Now you are ready to use your own FX make up.