You could try opening up the device and see if there is any damage to the ribbon cable connecting the display. Check it for pinching, bends, cuts, looseness, etc.
You might also want to try turning off the laptop, plug in an external monitor, turn on the external monitor and then turn on the laptop. If you get a display there, then it may well be the attached display needs replacing. If you still can't see anything on the external laptop, then it may be the graphics card that is going.