Guys, truck previously had chrome fender flares on them. Since I have taken them off, the spot behind the wheel on the wheel well has had some paint come off due to rust. I'm going to get the bad paint off and get it down to metal, prime, paint and clear it. My question is where in the process do I feather the "new color" into the old color, and what is the best way to do it? I would think with masking it off I would leave a sharp line. I can sand that edge, but I just want to know the best way to do it. Luckily it's not a pot you really see, but I woudl like to know the best way to do this anyway. Spot is really only about 3/4" wide and 3" long.

Thanks for the help.