Touch up paint

I used some Duplicolor touch up paint on a few rock chips a few days ago and as I was doing it I noticed the brush that comes with it isn't that great. It's too large and it made it hard to get the paint evened out. I did my best and thought maybe it would even out as the paint dried, but it came out looking like crap. I tried applying some clear coat over top hoping that might help, but it really didn't do much either. What would you guys recommend doing to fix this if it's possible? Do I need to find a small sandblock and re-do it, or is there a polish that could help even it out?