Not long ago I had a small bulge behind my ear.To me it appeared to be a swollen lymph node.It was about an eighth of an inch in diameter.In two to four weeks time in went down.I can hardly feel it now not unless I press hard where it was.What could possibly be the cause of it?

Viruses, sinus infections and the like cause swollen lymph nodes.

In my previous question,I should have also asked if the lymph node in question has disappeared within the two to four weeks time does it mean the virus or infection which caused it has now gone.

Typically, yes, that is what this means.

Also, please answer here. Just scroll down to the Quick Answer and post your response there. No need to start a new thread.