Well if the device is still under warranty, then you should contact the manufacturer.
If it isn't under warranty, then first I would try turning it off. Connect an external monitor, turn on the external monitor and then turn on the laptop. Do you get the problem on the external monitor as well?
If yes, then your graphics card/GPU (and possibly the motherboard) will need replacing.
If the external monitor shows just fine, then you need to check the connections to the attached display. Check the ribbon cable that connects it and make sure it isn't loose, disconnected, bent, pinched, damaged, etc. You may want to unplug it at both ends and then reconnect to see if this resolves the issue. Should this not fix it, then you may need a new...