I installed a 3X5 Wedi shower pan (fundo). I am ready to tile it with mosaic. Unfortunately, I put a dimple in the surface of the pan about with my heavy knee about half way from the edge to the drain. A small amount of water collects in the base of that dimple. Should I fill and fair (feather) the dimple with thinset or urethane ? Obviously, I'm trying to avoid having to rip out my pan and starting over. I'm also trying to avoid a situation where water is absorbed through the tile, into the thinset, and into the base of the dimple ? Any help or comments?