Hi Kathy!
I don’t know if you remember me, but I met you at the sprint tri in Playa Del Carmen earlier this year! 
I am so sorry to hear about your pain. I have a saddle sore right now that I just got antibiotics for…it’s been hanging around since I was in Mexico. In my case (it is in a different area than yours), I lost weight and my shorts would get all the more loose when I would ride and sweat in the humidity of Cozumel. Wet, baggy spandex chafing the crap out of me – ugh!! My problem area is where the leg joins the crotch – that area.
I just thought I would throw the idea out there of getting antibiotics for your sores. I’d been swabbing the spot with rubbing alcohol and using polysporin, but it was still hanging around. (i.e. I could squeeze a little bit of pus out of it every morning – nice.) My doc just prescribed this antiobiotic (mixed with other stuff) cream. I apply it once a day. It sounds like your sores are not healing, so I wanted to write you and tell you about my experience.
In my case, there is also a hard ridge of either scar tissue or other crap that may have to be excised (frigging excised!!) and then stitched up. I am waiting until after IMCoz for that though. (And crossing my fingers that I don’t have to have that done. CRAP. lol!) In the meantime, I changed seats, and wear tight proper fitting shorts and so far so good.
Good luck to you – I really hope you can get this resolved quickly and you do not have to suffer anymore!!!