Got an ob/gyn? I'd get it looked at. If I had to guess, I'd guess a friction scrape during intercourse and perhaps it is infected. Most superficial little cuts heal on their own but that's a trickier area. In my opinion, you are at the 'when to see a doctor' phase of this article. https://www.medicalnewstoday.com/articles/325100#seeing-a-doctor Don't be embarrassed, seriously. everyone has sex and they just want you to be in good health, pain free.