There was an ant crawling in that space and I used my fingernail to kill it, and suddenly I heard a pop and noticed the crack. Is it only cosmetic or is it a major issue? How much is it going to cost? I live in India btw
MacBook Air 13″, macOS 12.0
Both ends of the crack appear to terminate at the screen's edge. In my opinion the crack is not likely to propagate into the image area, and is merely cosmetic.
Fixing a broken screen is expensive; on the order of $1000 US. AppleCare+ (Apple Care Plus — if you bought it) covers such damage (with a deductible).
At least the insect is dead.
Cosmetic Damage
