We have a one-piece shower unit in our master bath. Noticed that the wall between where the shower head comes out of the wall and and the top of our shower unit is soggy. Did not use the shower for several days. Wall dried out and after two or three showers it was soggy again. The master bedroom closet is on the other side of the shower. There are no water marks any where on the closet side of this wall. What's the best way to proceed and figure out where the leak is coming from.