Black shadow appears at the lowerend of my iPhone 8+ screen?
So my phone hasn't been dropped recently tho I did receive it through a courier service but it was tightly packed, there's a black sort of shadow that appears on the lower end of my screen only sometimes, it quickly disappears if I readjust my brightness. First time it appeared I restarted my phone and it was normal for quite a while and it appeared again but I changed the brightness and It got normal again. I'm concerned is this going to get worse and is at a hardware issue ? Do I need to be concerned ?