I will guess that you are correct. It's an LCD screen, or the internal video cable. More likely, the screen.
Either way, take to Apple. If you are in warranty, or have AppleCare, Apple will sort it out for you.
If you are out of warranty, take it to Apple, or call AppleCare. They can fix it under their flat-rate repair program. Cost you around $300-350.
That fixed fee service can't be used to repair accidental damage or liquid spills. The repair center will fix failed items that would normally be under warranty, when you MBPro is no longer in warranty.
Your MBPro gets shipped to Apple's central repair depot. You get it back within a week.
All fixed. Whatever needs replacing, gets replaced - all for the same fee. It's a good deal for a major repair like you need.