[HELP] MacBook Pro A1278 LED Screen Problem

From YouTube videos that I've watched, the LED screen is overlaid by a plastic glass-like that keeps it in place and removing it requires heating the rubber underneath the plastic. It made me wonder how could anything slip in between the screen and the plastic if it has been closed all this time. Here is one of the videos I watched:

The pattern is fixed and always there no matter what, not like a smudge that could be cleaned.

I have not tested it on external displays yet because I just ordered a mini displayport to hdmi converter and it hasn't arrived yet. I'll update when I have. Looking at the current virus situation, it may take awhile.

For 10 years I have this MacBook, I'm pretty sure I have never spilled or handle any kind of liquid near it.

Given the age, I'm aware that downgrades are inevitable to any electronic devices, but it would be informative if someone else had the same problem who may have solved it before.

Keep in mind that few and I'm among them remove or dissect the display. The FRU on this is the panel. You seem to want to take it apart so my advice is to find the parts then see what you see on YouTube.

If this hit a shop they would change out the panel.

Figure 26 to more dollars to fix this.
https://www.google.com/search?client=opera&q=MC374LL%2FA+LCD