Normally I don't like to crap on people's projects, better to say nothing. But since you asked, I'm going to offer my feedback. Take it in the spirit of wanting to help.
I wouldn't give up, you can do this. But I'd start over completely. It's not working.
First off, if you haven't seen it yet, this thread is awesome for looking at a variety of paint jobs, styles, and colors:
https://pinside.com/pinball/forum/topic/metallica-post-your-custom-painted-sparky-here
Good reference, take a little time to look at them, and maybe take notes on what you like (or don't). See if there are some consistent ideas that work for you. For instance, note how every single one matches the lip color to the face color. It's pretty awkward looking to give him lips with a different color. He's not really meant to, because the sculpt is trying to capture the feel of line art.
The red you chose is too much, it's true, but that's the other thing making him look like a clown, the lips contrasting like that. I would suggest picking a face color, and sticking with it for all the skin. It will match the tone of the sculpt much better, and you'll be happier with the result,
I would use a spray primer to prime the whole sculpt. I like using grey myself, it provides a good foundation for colors. Your paint will stick better, and go smoother and less streaky with primer under it, and it will hold up better in the long term as well. Worth the time an effort. And it gives you a blank canvas to start with.
Use acrylic paints. Go to your local craft or art store. Take a look at the colors, and see what strikes you. Take a list or sketch with you of where you want what color. Want his skin to be a light, corpse-like blue? Note that down, and see if you can find the right color at the store. Or close enough. Easier if you don't have to custom mix your main base colors, and take them straight from the bottle. Way easier later to do touchups, don't have to try and recreate your custom mix.
But you can definitely mix some colors too.
For the chair for instance you could buy 2 browns, a light and a dark. And mix them just for a middle accent color. So lay down a coat of dark brown, then dry brush (drag your brush without much paint on it over the tops of the ridges in the wood, so you just pick out the high areas) a mix of them them. Then a lighter dry brush on top with the light brown.
Look at colors that aren't too vibrant. His skin will look more natural with a light, chalky blue, than it will with a really deep, saturated blue. That red you used is too bright and RED. It looks like candy lip gloss. Think more tonal, lighter or duskier.
With acrylic paints you get what you pay for. The cheaper they are, the less pigment they have. That means they don't cover well, and streak. Take more layers, more time, more chances to make mistakes. So if you can buy $3.50 bottles of paint instead of $0.99 then spend the extra cash.
Pick up some small brushes while you're there, a detail brush, a medium coverage brush, and a bigger brush that's cheap because you're gonna wreck it. Use it to drybrush, which just ruins brushes. Get all electric-socket-hair looking.
Paint your base colors, learn about what drybrushing can do for you to bring out highlights. It's a trick you can use all over the figure to add depth, and it's really easy once you learn how little paint it takes. Seriously, your brush should almost have no pigment on it. You could tap it down a paper towel and not really make a mark. Once you start dragging those brush fibers things will slowly come to light.
Hope that helps! It's really worth it to take the time, plan it out, and do it right, you'll love the end result much more I think. Update us if you do, or ask questions.