I hope this does not seem too simplistic but the advice to use tea tree oil is good. I have not tried it as a stand alone solution for this but did try it with yogurt as an implant. It did help but no cure. But recently when feeling like you sound, in desperation, I grabbed honey added a couple drops of a tea tree mix to it and found almost miraculous relief! after a few days I started to even FORGET THE ITCH AT ALL...
But after considering the links in my own post I decided to try it at least twice if not 3 times daily for 2 weeks... like a prescription(maybe the drs have that part right!)
This is the first time in years I have felt free of the uncomfortable if not horrendous feeling in that area of the body... You have my sympathy and hope something works for you...