There's no way I know of to match the sheen of a sprayed satin finish. Frank Ford suggested to me once using a mini sandblast gun; that does look better than steel wool but still not perfect.
I had a friend who started developing a "receding hairline" so he shaved his head.
I'm only half serious but you could use superfine steel wool over the whole back and sides to make it all the same.
Harbor Freight has an "air eraser" in the air tools section, same location as the airbrushes. It's about $20, IIRC, much cheaper than the usual Paasche or other higher end version. Cheap enough to experiment with. Probably not as good as the pricier version (I have no way to compare), but very adequate. Also, a trick used by model builders to clean parts for painting they don't want worn away by grit is to use baking soda as a medium--much less abrasive. YMMV, try on a scrap first, NFI, you're on your own, etc.
Any word on how this turned out? I've got the same problem on a Taylor that's on my bench right now, ovangkol back and everything! Looking forward to any responses.
Don't bother. You will just have to do it over when that crack opens again.