I am trying to replace the bottom sheet of drywall in my bathroom and laundry room. However, I was under the impression that I should remove the old paint to expose the face paper again. However, when I scaped the paint, a lot of the face paper tore off and now a lot of it is brown like a paper bag. Should I replace the upper sheet as well or will this not be a problem? A friend thought this would degrade the moisture protection especially in the bathroom, is this true?