What is this Vertical bar of Inverted Colours on my Macbook Air Screen?

I was cleaning my Macbook Air at the weekend and think I might have damaged the screen. A vertical bar of inverted colours appeared on the left-hand side (the right was fine initially) but then both sides of the screen displayed as shown in the image.

After about an hour of doing nothing, the bar on the left-hand side returned to normal but the right-hand side bar has been there since.

I’ve tried:

• Pressing around the screen (does nothing)
• Cleaning it again (gently and with no cleaning fluid)
• Connecting it to an external monitor (output is fine which suggests the GPU is fine)

Any ideas what has happened? It’s a 6-year-old machine but I’ve never had any issues with it until the weekend.

Does the screen need to be replaced?