Dead pixels show up differently depending on the background colour, so we show several. Look at each colour slowly — a stuck pixel looks like a dot that never changes.
Dim the room a little, or use normal indoor light.
Hold the phone about 30 cm away and look straight at it.
Scan each colour row by row. Most defects hide near edges or the camera hole.
If something looks wrong, long-press that spot to mark it.
What you are looking for
Stuck on: a bright dot on a dark background.
Stuck off: a dark dot on a light background.
Colour defect: a dot that looks tinted, clearest on pure red, green or blue.
Uneven brightness: a patch that looks lighter or darker than the rest.