Redness And Irritation?

Hello there,
right after I got my period, I had a bit of redness and irritation on the outside of my vagina close to the hymen and butt hole. There's a part on the right side of my vagina that seems to be rubbed raw, and it's sore. The other part that is sensative is where the hymen is. This just occured after my period. Does anyone have any suggestions to what it is? It's just red, not itchy, but sore, as if it's almost like a rug burn! :cry: it hurts!