I'm having an odd problem with my 3DS. Occasionally, the top screen wil become very dark. If I apply slight pressure onto the screen, it will return to normal, until something pushes down on the back of the top screen. I can change the screen's color very easily depending on where I push. Sometimes the color won't stay normal for very long, but a restart of the system seems to lower the frequency of this occuring. I haven't dropped the system at all, or anything like that. What is the issue? Does it call for a repair?