Not on a steel frame. I might worry just a little if it was titanium or AL. I'd worry just a little bit more if it was a dent in carbon fiber. But I'd ride on all of them and keep an eye on it. I probably wouldn't put a sticker or decal on it so that I could inspect the area every month or so. if the paint is chipped to where you can see metal, I'd recommend something like clear paint or fingernail polish to keep rust away.

Hillrider beat me to it!