People have mentioned PAX on this thread already. I feel I can elaborate immensely on the subject. PAX might be the way to go, especially if you're looking to use acrylic paint. I'll give you my general copypasta PAX reply so you can educate yourself. The best part about PAX paint is that you pick and blend the shade yourself.
You need a soft body acrylic paint
and pros-aide body prosthetic adhesive
. The very first time PAX was produced for a theatre production, Liquitex was the acrylic paint that the artists used. Its pretty much an industry standard for acrylic paint.
You can mix PAX in different percentages. The basic percentage is just 50% paint and 50% pros-aide, but there are some cosplayers on this site that used different percentages. You can hunt them down, contact them and learn what their experiences with their percentages were, but for most applications 50-50 is effective. You can mix small batches and test the viscosity and coverage of each mixture to find your favourite.
Remember that after you apply it, it will be insanely sticky. You cannot bend your arms or touch your fingers or any folds of skin together or they will stick and tear the finish of the paint. And you fill probably find that you will need more than 1 application to get a vivid finish. After it has been applied and dried to the colour you want, you have to powder it profusely with a translucent powder. Then it will last all day and won't come off unless you actively pick and scrub at it.
When you buy Pros-aide, remember to buy pros-aide remover
. Its a liquid solvent that will break down the sticky molecules in the Pros-aide that is maintaining the structural integrity of your body paint. This will make taking it off muuuuch easier. It will take some scrubbing though. It might look peculiar on your fingernails if you have really bad hangnails like me, and will hurt if there are open wounds or anything, so make sure you've been taking really good care of your nails before you put the paint anywhere near your hands.
Make sure that you have removed long body hair from your skin before you apply or it will hurt a lot when you try to take the paint off. Pros-aide sells a shave cream
that it swears by. You can also use this to prep your skin for a whole day of not breathing while its encased in a rubbery paint.
Finally here's a topic on PAX
by someone with a lot of experience using the paint mixture here on Cosplay.com. Check out her profile and look at her body-paint costume to get an idea of what full body paint with PAX will look like.
And this is a link
to the special effects wiki on PAX paint to educate yourself on the subject.
Copypasta aside, you can use this stuff on your face. You MUST set it with a powder. And you may find having a friend do this for you is more effective. If you choose PAX, you'll develop your own preferences for it, since it is an entirely home-made substance.