Blinking horizontal lines on screen, disappeared and reappeared

I have a 2012 MBP retina and the screen just started showing a few blinking white horizontal lines on the screen. Later it went away and then reappeared with even more lines. Over the past week now it has grown and there seem to bee hundred of lines making the screen quite unusable. Occasionally a large portion of the screen image will begin jumping up and down very fast making it impossible to even look at the laptop.Does not happen on external monitor, the lines persist in recovery mode and after resetting NVRAM and SMC. I also tried reseating the logic board cables.

I felt like this may have began after I updated to OS Mojave but can’t be sure. I have no ability to get it repaired at a shop due to my location. Would it be worth it to install a different OS version? Order a new display cable abroad? Or purchase an entire new display assembly and replace it myself (I did this before actually after i dropped the laptop 2 years ago).

Thanks so much for the help!