well yesterday night... i was being fingered by my SO, and the usual routine started to become quite painful. i was close to my second O of the night so just forgot about it and continued to cum. after i was done it started to hurt even more... kind of a sore feeling that I've never felt in that area before in sexual acts. so quite worried we started investigating what was causing the irritation and then we both spotted it. to the side my hole one of my virginal lips had swollen up , so it appeared. it was sore when i touched and looked like it had been filled with liquid just like a blister. i went to sleep worried and as soon as i woke up the next morning i checked it to see if any change had taken place. It was back to normal. there has been no problems since then but has anybody got any suggestions or ideas of what caused this irritation? neither me or my SO have ever uncounted an STD so that ruled it out for us but I'm scared and am curious to know what caused it or what it actually is.