Are those dead pixels? "Dead Pixel Detect and Fix" apk did not work with them
Dead pixel is a class of manufacturing defects on screens which causes a pixel or sub pixel to remain permanently on or permanently off. The actual cause of dead or stuck pixel varies, and while some may fix itself over time, but many are permanent. Basically, as long as the pixel are stuck on a color that it shouldn't be, it can be considered a dead pixel. So yes, you have a dead pixel.

Depending on the device, the number and type of dead pixel, the manufacturer, and the seller you buy the item from, dead pixel may be covered under warranty. Check your warranty information on how to get a warranty and also ask the store you buy your device from, and you might be able to get a replacement. If this is a brand new device, some stores may replace even when the warranty doesn't require them to (under store policy, not manufacturer's).