Are there any noises coming from the PC? Can you hear the cooling fans working normally? I suggest you to test the laptop with another monitor, or using a TV. This way you can confirm if you are facing a screen issue or some kind of hardware damage. If the laptop is working fine with another monitor, you may need to check the internal connections. If it is now working, I advise you to consult a technician to check what part has been damaged and if it is repairable. Have in mind that this can be a connectivity issues which are easily solved.
Hope this helps