Saw this thread and it reminds of what an old Biology teacher of mine once said when someone conveyed a similiar story to him in class once.
"When you are asleep, most often then not you have your mouth open for a period of time, I wouldnt worry about your ear, just the thousands of bugs that will crawl down your throat in your life time, it happens to everyone and best of all usually you dont even notice it!"
This kept me sleepless and on guard for many weeks! Once you get to grips with it its ok though!
Have a fantastic nights sleep everyone!