Most homes in the Houston area have textured walls, usually orange peel or knockdown. When a hole gets patched smooth and painted, the patch shows as a flat, shiny spot, especially when light hits the wall from the side.
A patch only disappears when the texture around it matches the rest of the wall. That means repairing the damage, sanding it flush, then spraying or hand-applying texture at the right thickness and pattern, and letting it dry before priming and painting.
Water damage needs an extra step: finding and fixing the source, then cutting out soft or stained drywall rather than painting over it. Stain-blocking primer keeps old water marks from bleeding back through.
With 23 years in construction, texture matching is everyday work for us. It's the difference between a wall that looks repaired and one that looks like nothing ever happened.