In my opinion, if you have an area this large (over a foot as you say) I would 'panel paint'- that is, mask to a body line and completely repaint that whole panel. To blend in that large of an area is difficult. If it is a custom mix color it is even harder, but a solid is pretty easy and will look much better than trying to blend all the edges of the damage. Mask, sand, prime and paint. I prefer a gun and no aerosols for something over an inch or so. Good luck- time will make it look good- take your time to work it well and it will be worth it. 