How to remove stain from pavement after having dropped sulfuric acid on it?
You did the right thing by neutralizing with a base.

The best solution is to let time heal the stain. The surface is obviously damaged, but there is no way to reverse that damage. The stain will only go away if someone keeps on scrubbing the area until a new surface is exposed. The good news is that dirt, soil, and water will slowly remove and even scrub away the (temporary) surface stain. Maybe keep a flower pot covering the area for the time being.