Welcome. I'm not for sure how you plan on attacking this, but if you just want to "touch-up" maybe just do it with a touch up brush.
If you plan on sanding and blending, you may want to try a jam gun
Jam guns are great for smaller areas
Most definitely BUT when you airbrush, the metallic colors tend to turn out lighter than what it's supposed to be. I guess because the metallic flakes come out different than a regular gun.
If it's a solid color you are painting, then this will work out better.
Metallic flakes can clog or make the airbrush sputter if they are too big in size. Plus like I mentioned, the way the come out of the airbrush makes the metallics lighter than you would think.
I would suggest something like an Iwata W-100 or a Iwata W-101 for smaller jobs. You can adjust these to a very small pattern if needed. They are also fairly inexpensive. They can also do medium sized jobs as well.