I bought the factory touch up paint kit from the dealer, the paint matches ok, but the brush it comes with is complete and utter garbage!!!!!!!!!!!!!!!!!! LIKE, TERRRRIIIIBLE
You need a good pointed touch up brush like a detail shop would use.
I used to work for one, and the paint guy that did touch ups would fill the chip with paint off these little horse hair brushes, touch it up with clear, then sand and polish it smooth to match the factory paint so it didn't stick up, he was really good. he did a blend on my bumper where I backed into a cement post and scuffed the paint, I could never tell where it was, granted, it wasn't a rock chip touch up, he sanded and resprayed like a 4x6 inch area.