How do you add texture back to a previous painted wall where drywall mud had to be added to smooth out where some drywall nails were bulging (coming out) out from the drywall. I banged the nails back in which left a indentation the size of the hammer head. After adding the mud and sanding it smooth, the newly painted surface (some places as big as 4"-6"diamter) does not have the same texture. The house was built in 1978 so the texture on the wall is not much, but when you paint over the spots where the smooth drywall is, it is very noticable.