Laptop screen damage?

I bought laptop 2 days ago and it happened all at once

I have warranty but is that synonymous for screen?

If used improperly, you have no guarantee.

That would be the case if it fell to the ground, e.g.

If you have not caused it yourself (eg What has come between keyboard and monitor) then there's the Grantie.

No, but it was an exhibitor

This looks very much like falling damage, or that he was closed and something was in between. I would doubt that anyone here vouches for the guarantee. The reason is so easy to determine.

It was an exhibitor can also have happened there