My wife has an old black Nikkormat Ftn that looks like it was dragged behind a truck down a gravel road. It's all dented and about 30% of the black is missing. She won't let me or anyone else touch it. She says it shows its history and has character. She also thinks it makes her look more professional, not that she is, because the camera looks very used. So you could go that route.
Or, you could try to find some Kodak black brushing lacquer, although I'm not sure they make it anymore. Or, get a can of satin or flat black spray paint, and spray a little in the cap. Then using a small brush do your touch up. Have some mineral spirits on hand for quick clean up, as the stuff dries fast. Follow up the paint with a little car wax to even out the lack of gloss if needed. I gave up on my F3s looks a long time ago, as the touch up wears off fairly quick. Good luck, and just have fun with the camera and your photography.