I wasnt doing anything special, just browsing around the web when this happened. My screen went very bright and it inverted the colors. The shortcut for inverting colors does not work. Have no idea why and how to fix it, but it got me really scared.
Yes, it sounds like a hardware failure.
You can take in for service, Apple should fix you up.
Just curious, last time I saw something like that occur some time after a liquid spill.
Strangely, that one took several weeks to appear, but it was an older model MacBook.
If you have Apple support in your country, you could certainly call Apple. They may have an option to ship it for service
You didn't say if you have tried the various hardware resets
Try both the PRAM and SMC resets. That Youtube video that you linked showed that some folks used a simple reset to get back to normal. It just takes a couple of minutes to do both, and it either helps, or no change...
I see you are using an appearance theme of some kind. Be sure to try removing (uninstalling) that theme completely, or setting your system appearance to defaults.
However, as you said booting to the Recovery partition still showed the same problem, then I don't expect that to help either - but you never know, software that affects the full appearance might be causing unintended issues, too.
The image retention (ghosting) that you see now is likely from your screen being over-driven. That will dissipate if you remove power, and let your MBPro sit powered OFF for 24 - 48 hours.
Did you contact AppleCare yet?