AHA! Spike-It Lure Dip Black!
I would be afraid of most paints and markers, that they'd leave an odor, possibly an offensive one.
Me personally, I try to avoid dipping baits if I can, I like to keep the least plastic possible, especially when rigging Weedless, so there's less Plastic for the Hook to contend with...but that's just my thinking. Just dipping the Head/Eyes...the Lure Dip on a Brush, Toothpick, etc., then dipped would probably make KLK's New NASTY Shad!!! lol