On Modern (Clear Coat) Cars There Is A Reason Why Professional Auto Body Shops Paint Entire "Panels" and Blend The Paint Into Adjacent Panels And You Just Described It.
Insurance companies, as frugal as they are, will even pay hundreds of dollars more than it would cost to touch up a small nick or small repaired dent for this reason. It's the only way to do the job right and have it not look like heck.
If one could, " . . . repair a small rust spot myself," that would be great, but usually one can just try and do a little cover-up and change the rust spot to a different color.
You are sometimes more likely to get away with a decent touch-up if it's down low, not at or close to eye level.
Try it. I doubt it will look too much worse than the rust and it will probably make you feel better. Try and keep the spot small. Be careful. Don't enlarge it.