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?
Something has happened to the LCD crystals, and the only way to fix it is to get a repair. Whether or not to get a repair is completely up to you. If the slight discoloration interferes with gameplay, then a repair is recommended. You can schedule one by calling Nintendo at 1800-255-3700 (6m-7pm, Pacific Time, 7 days a week).