Thanks for your question.
From what I gather is that there can be a likelihood of an STD. I would advise you get yourself tested. Your Local health clinic can provide you with a complete and confidential testing if you so desire.
Another possibility could be that the sensitive nature of the skin is due to a small nerve damage that may have taken place during the trauma. For your information the Nerves usually take to heal in a long time say possibly a year so it in all probability this area may now be healing. Any sort of pain from the nerve issues is many times known as as burning or tingling. It is easily intesifiable while the nerve heals.
I would suggest that you get yourself tested for STD's although this problem does not at all look like an STD problem.