I noticed a dent in my right pinky where my phone rests. It didn't go away. Everyone I know who uses their phone a lot has the same dent.
The bottom corner of your phone presses on your pinky joint for hours. Over time, it creates a compression groove. In severe cases, it can affect the nerve.
Solutions: use a pop socket, switch hands, take breaks, or use a phone stand at home. That little finger deserves a break.