Tower Controller reported an aircraft became stuck in the grass during taxi; but was not towed off the taxiway until the following day.

Narrative

Aircraft X was given instructions to taxi to RWYXX via taxiway 1. Aircraft X started taxiing the wrongway on 1. I told Aircraft X to make a 180 to taxi in the proper direction. Aircraft X made a wide 180 and got one wheel stuck in the grass. I called a tow from the FBO. After I got off the phone with the FBO I realized that the pilot had shutdown his plane and lights. He was no longer answering my calls on frequency. I continued to watch the situation from the tower using binoculars. I saw the tug come out to assist Aircraft X. At this point; the tower was a minute from officially closing. I went ahead with the normal closing procedures. I assumed with expectation bias; that Aircraft X would be towed off momentarily and that everything would be ok.I came in the next day and was told that Aircraft X was not able to be towed off during the night and was left stuck on taxiway 1. The airport management knew about it; however because I did not log the event nor share it with ATC management; the morning crew did not know what was going on. It led to a lot of phone calls and assumptions that maybe someone had crashed. I was tired and didnt properly plan for the possibility that Aircraft X would remain stuck on the taxiway. I assumed that it would be towed off within the next 15-30 minutes. My expectation bias led me to think everything would be ok; thus not adding this event to the log so that the morning crew would know what happened just in case. I also should have called an Alert 1 and notified ATC management about the situation.