Hi there. I think we're all just guessing here. You are in a monogamous and sounds like long term relationship and have used condoms. While anything is possible, I do sort of doubt it is an std like syphilis at this point but he sore sounds suspect. There are other things that it could be. The ingrown hair is something that can really happen too. Cyst. We just aren't sure. It needs to be seen by a doctor hon. Please let us know what happens!!
Have you had any unprotected sex? I'd be guessing an ingrown hair or cyst as the most likely possibility, but if you have had unprotected sex, it wouldn't be overly cautious to get checked for an STD.
Hello and welcome to the forum. This article may help you. https://www.healthline.com/health/womens-health/ulcers-vulva#causes It lists several things that this might be. It could be viral, fungal or bacterial. It could be due to an autoimmune problem. It could be a simple skin reaction. Does it itch at all, by the way? And yes, cancer is on the list but the percentage of people that this turns out to be the case for is small. But, you should get it checked out. can you see your doctor?
Looks sorta like a cancer sore. No stds or anything like that