If you do over apply, do not attempt to wet sand it down like the YouTube videos. Our paint isn't on there very thick you will end up wearing the paint around the touch up spot creating a half moon spot. I learned the hard way and had to hit it with touch up again several times. Wish I would have just left it alone.
I have heard good things about Langka. Google it or go here.. http://www.langka.com/
If I were to do it over I would try this.