A.H.
I had the same thing happen with my 2nd and third. I would rub on some baby oil when it got super bad. Also try to rinse down there, with some diluted vinegar. (50% should work ok)
It always took the sting and itch out for a little while. Other than that, I don't know what to say. I never got an answer either (it wasn't an infection), and it went away after birth.