Light at top left corner of iPhone 12

A green light has always been in the top left side of my iPhone 12. It turns yellow and red sometimes -as well. Sometimes when I touch it the phone goes to the phone dialing pad. Some say the phones damaged but the only fault I have is a greenish hue sometimes on the dark parts of some videos. I read that I should update to a higher ios so I upgraded to iOS 14 with no change. Any body know about that?