I've had my Holeshot for a while now and have swam in it a dozen times this summer. I had a "fine jewelry" shop replace the battery today and after swimming for half hour, now there's fog under the crystal. All of the hands work, and it's still tells perfect time. Has anyone experienced anything like this? Or does anyone have any suggestions? Should I be concerned? I have no idea how to remove the back so I haven't looked inside. Any help would be appreciated.