That looks like a wound to me. Can you handle your bird enough to investigate a bit more, and photograph what's under those feathers?
I can handle him or take a picture, but he won't allow both, lol! I did look him over a bit closer today and didn't see any scabs/deep scratches or anything concerning. In fact, looking him over today I wonder if maybe it could have been the angle I was looking at him through. This area looked much more "normal" today...
I guess I might have jumped the gun to freaking out... he still chirps, talks, eats, and forage normally. And he flies just fine.