You need a moment to sit down and think hard what you want. Because this post shows abusive behaviour. You are checking your GF's vagina and her underwear. You don't have the gyno background, but you have come to some conclusions. You've confronted her with it and she MUST be lying about her body, according to you.

This is crossing some big boundaries. How would you feel if she'd be doing this to you? This is not about a health problem, while that very well could be a factor.

If you don't trust your GF, you talk to her and you tell her you want to break up. You don't check her genitalia. You think you have evidence with this time, why is she still your GF? Why are you putting her in the defense instead of just splitting up if you don't believe her?