I've ran into a bit of a problem when painting a wall in our home today. We're in the process of redoing our stairwell, and one of the walls had a fairly noticeable paint run in it. The wall itself is a relatively small surface area, and so I decided to sand the wall down to remove the run. After wiping the wall down and letting it dry, I repainted it. The wall is very patchy / blotchy looking, and you can see "dry" spots all over it when light hits the surface. How do I go about fixing this?
Should I have primered before repainting? The paint we're using is Valspar with Satin finish. If primering wont fix the appearance, would putting a thin skim coating on the wall help? I was thinking it may help even out the surface a bit, and then i can just prime and paint that?