black line at the bottom of top screen

Out Of The Blue My 3dsXL Has A HUGE Black Line At The Bottom Of The Top Screen It Covers At Least 1/4 Of The Screen And Is Very Irritating. I Had It For A Year And 4 Months And I've Rarely Dropped It. I Woke Up Early This Morning And It Was There All Of A Sudden. And What's Really Even More Weird Is That It Played Perfectly The Day Before