Iphone X Green Line in LCD

I suggest that you first try a "soft" reset on your iPhone. If this green line reappears, then you should make a Genius Bar appointment at your local Apple Store or Apple Authorized Service Provider to have them take a look and provide you with your options.

Ref: Apple iPhone X Reset Guide - iKream

This problem is often caused by water damage, check if the indicators in this phone are red-rose ( water damage). If they are white that means it’s not damaged and the problem is somewhere else, but if it is red it is possible that some water got in and caused your screen to do this.

It might be a very bad thing, tell us if the line becomes bigger with time (pixel death).

If not Imight have an idea of what is happening, could you please press (not too hard) on the RIGHT side of the screen. |__|<- —> | | <— ( this place is little lower than your back camera) in this place the motherboard connects to the screen. If it works ( it won’t disappear forever) but if after 10-15 seconds the line becomes smaller I will tell you what the problem is.

See if the following can help: Find Locations - Apple

Hi

This is a screen hardware fault make an appointment at Apple store

Or an approved apple repairer.

Cheers

Brian

Did you buy it in store or from somebody? If you bought it from somebody he might not told you about the problem, if you bought it from the store and you have the warranty feel free to repair it.

Not sure what you mean by a "new BOX pack", if you mean it was sealed then anyone can get a box resealed.