I’m having the same problem, although much bigger I think. My display has 3(!) cracks which take out 40% of the screen. In other words; the MB Air is useless.
Prices quoted to replace go indeed up to usd 450-500, and there is no alternative yet, as there is no ‘do it yourself’ manual.
I’m afraid I need to wait until a person with knowledge uploads a manual. (and the replacement screen is available to buy online)