Female Himalayan in heat

Question
My female Himie was in heat a few days ago (not for the first time), and my male Himie attempted several times to breed with her.  This was the first time he has attempted this.  A little while ago, I noticed that she was cleaning her hind-quarters, and her anus seems to be extremely swollen and red.  What do you think could be the cause?  I am calling the vet in the morning, but would like to know if there is a possible cause.  I am very worried.  Thank you in advance!  

Answer
ok first....some information for you, just in case you dont know....

the male cat penis has very sharp barbs on it, and during copulation, when he climaxes..the barbs come out, poking her vagina very roughly, this stimulates her to ovulate. if they have only had sex once, she wont be pregnant, he stimulated her to ovulate the first time they had sex.

now..i think her anus is red and swollen because it is so very close to her vagina, which now is probably sore due to the barbs on his penis.
she will repeatedly have sex with him even tho she is sore.and she will ovulate each time they have sex, so you can count about one kitten for each copulation except the first time.

i am not entirely sure about this being the reason for her swollen , red anus, but i dont think its anything to worry about until you can get her to the vet.