Went to the doc yesterday. He's an expert.  I had a fissure, but I don't have it now.  What I do have is a very small, persistent irritated skin area at the site of the fissure.  It is small as a lead pencil head. The Doc prescribed nitroglycerin.  I don't have any experience with this.  Will this go away eventually?  How long?  It is bothersome.  I have had this condition for two months now.

Sounds like your describing a "skin tag". I've had very small ones like that too and yes, they eventually went away. Yours may go away too.
How long did it take depends on a few factors, not the least in which how well you take care in keeping your stools soft, etc.
The Nitro was given because it helps promote blood flow to that region (thereby promoting healing) by reducing tightness or spasming. But you have to be careful of its side effects (mainly headaches) so apply it judiciously.
For more tips on using the Nitro click on here:
http://www.medicinenet.com/anal_fissure/page3.htm
Hopefully, eventually that skin tag will just get smaller and smaller and the irritations will become less and less bothersome, and before you know it, it will be gone. But this can take some weeks if not some months.
GL