Black strip on one side of the screen - tab S

My tab S has a black strip about 3 cm thick on the left side. I can not see behind this black strip but the tab is fully functional. My daughter was using it in the car and when i looked at it a few hours later it has this on it. The tab wasn't dropped or sat on so i am unsure how it is caused and how to fix it. It seems to be the internal screen that has this defect.