Any sore or abrasion on the skin will result in burning when urine hits it. Similarly, if the soreness were due to herpes we would expect to see small "water blisters" forming in the area that is uncomfortable. This does not sound at all like herpes to me. At the same time, if there is a visible lesion present, I would suggest that this is the perfect time to have yourself examined and tested by a trained health care professional--your doctor or at your local STD clinic.
Hope this helps. EWH
I have read plenty about std's just because it is good to be familiar with the knowledge out there about it, I would not think it to be herpes, because there is only one. there is an awesome website I go to for everything it is called webmd.com you should try it. we all get normal bump from time to time, and it could also be a pimple or something similar. U should still go get checked in about a month, and to be safe don't have intercourse with anyone until you know.
And also if she is your friend why don't you ask her if she has ever had herpes, you would not be out of line just ask her in a sensitive way..hope everything goes good for you.