So here is my problem so i have an iphone 4 and it is my first iphone to own and hopefully not my last . So when i brought my i phone and few weeks after owning it i have noticed a stuck red pixel on the screen and it was just awful

and i have decided to change my screen and the problem was gone and everything was perfect and btw i have no warranty so i changed it with my own money and i didnt go to apple care too expensive

(bad idea) . After changing the screen and while watching some youtube i have noticed this awful looking weird thing on my screen which can only be seen when the screen is black. I am new to iphone and i reAlly need your help , any help would be great. Thank you in advance.