Beth-Ro,
You just PERFECTLY described my current problem, exact same spot, same medical response. I had an enormous bump over the summer and went to the gyno. I assumed it was an ingrown hair. the gyno was at a loss, positing that it may be a staph infection, a Bartholin's cyst, etc. She sent me to a specialist who said it was probably just an irritation due to my job and would get better over time(I am a bike messenger).
Using hot wash cloths along with a medication prescribed for the alleged staph infection the problem went away but my labia stayed swollen MONTHS later. (Did this happen to you? It is very distressing to see my body change and not know if it will go back to ever being symmetrical)
Now, once again the large bump has reappeared. I am going to try your method because I don't have health insurance and can't afford not to ride. but I have a few questions first:
You said you inserted the sterile needle into the vein. Could you actually see the vein or did you just insert into the bump?
What came out? When you used the needle was it simply a matter of draining a liquid (pus), or removing an actual clot?
I am so glad you posted your experiences. Although I know other female messengers I do not feel comfortable discussing this with them.

Thank you.
- rudie