Well, no one on the internet will be able to diagnose you. Believe it or not, it could be an ingrown hair. Or a little harmless cyst. Playing around with it doesn't help and may be why it is now getting painful. Also, we can cause an infection messing with something due to bacteria on our fingers. So, try to leave it alone. You can always see a doctor and that would be wise if you are concerned. Hernias really wouldn't form in your labia so that is not a worry. good luck