I've successfully used
LAB METAL on frames to be powdercoated. JB Weld on painted frames. I wouldn't refinish a frame just because of a dent that small, but each to his/her own. Get your finest model detailing brush and a jar of yellow paint. Clean the dent out real good and paint a microscopic smiley face in it. That way, it adds a little surprise to anyone who actually looks at it and notices what you've done with it. Class. Not classy, but a display of class and style.