Actually this happened to me a few weeks ago during doggy sex...

...In haste, he came in at the wrong angle...I tried a couple things that did not work...Finally, I did something that cleared it up just like that...I took a clean wash rag, and about four times a day went into the bathroom and got the water real hot...Then I would dab the wash rag into the hot water and immediately insert it in the crack area that was killing me...It felt good immediately...I would say within two to three days I was able to stop doing this....
I hope this helps you as much as it helped me....
Best wishes,
Caroline