Paint over Bondo

You never know how deep it is, unless you remove it. Someone may have skimped on labor getting all of the dent out. I would get all the filler out, inspect the metal under it and work it out if it needs it. All you want with any type filler is the lightest possible skim coat you can get by with. It's not made for rebuilding body parts, just for filling in small imperfections. A lot of people get carried away.