My master bathroom counter was installed today...but I am confused. The counter has a four inch backsplash. However, where the top of the backsplash touches the wall, the installers did not use any silicone caulk or grout to fill in the space. Also, my walls are not straight, so part of the backsplash touches the wall and other parts of the backsplash are a good quarter inch away from wall. I am worried that water will be splashed and drip down the wall. Should this area be filled in, and if so, with what?? Thanks for any help that you can give me!