I'm no expert but I am a woman...lol
Sometimes yeast infections can create sores, especially if your itching the area with a lot of vigor.
Here's the thing. You just won't know if you've got it unless you have an outbreak and go to the doctor immediately (within48 hours) or you get a blood test which will tell you if you have it but won't tell you where you have it.
I'm with the belief that you have to demand a blood test if your doctor isn't offering you one for at least peace of mind. Some doctors are just stubborn about it and refuse to test unless you have an outbreak of somekind. Go to another if you need to quit freaking out about it. The not knowing can drive you nuts and make you turn every little thing into something it isn't. It is a reasonable fear though since it is well known that it can be asymptomatic. It just doesn't hurt to have the blood test. It's your health and you have the right to demand it.
BTW I was just told on Tuesday that I have herpes (don't which kind yet). My doctor in his infinite wisdom decided not to treat with drugs until he got back the blood test saying proof positive that I had it. I'm really pissed about that now. We're , the doc and me, gonna have a chat about my health. He may be an expert on health and herpes but he's not an expert on me!