Intermittent Screen and Backlight Issue

Either way you have to replace the whole assembly unless you are up to separating the screen layers apart.

In my opinion, your screen is bad. Usually a bad drop will cause that.

However, you can open the back of your laptop, DISCONNECT THE BATTERY, then examine your LCD connector. Look for physical damage, or see if it is loose by any chance, or try to reseat it.

Use this guide, up till STEP 6 then jump to STEP 11 since at this point you're not trying to remove the screen assembly, just examining, and/or disconnecting and reconnecting it.

The pins on the connecter cable are fragile. Be very gentle, pull cable back not up; make sure it is properly aligned horizontally and vertically before inserting back. Otherwise the pins of the cable can get caught on the edges of the connector and you will have a damaged cable.

Alternatively, if you laptop doesn't look dropped and it is still under warranty, you can take it to an Apple Store or an Apple Certified Service Provider.