But flesh is difficult. It's not one color. When you go to Italy you will see paintings that are all green. That's because the red is a fugitive color and has vanished. They used to paint a layer of earthtones and green under the surface.
Most flesh has a lot of green in it.
So if you make your shadows green, then scumble over it with red, it creates the illusion of flesh. I've taught for years, and about ten years ago I became allergic to the oil paints. I can't teach in an institution that has solvent fumes. That's one thing that you have to think about as an artist early on, because you are working with all kinds of chemicals. You think 'oh that is because I just spent 18 hours on my feet working'.