Hi,I'm a 30 year old male,who has recently had unprotected oral sex about a week ago. Over the last couple of days the left side of my penis directly under the head has been very irritated. There is no rash or signs of a rash, but when it rubs against my underwear it is sore and irritated. Could this be some sort of an STD or is it likely just irritation that will go away on its own. I do not have any other signs that would suggest an STD such as visible bumps, rashes, itching, etc., or buring during urination. But nonetheless, my mind racing as to what it could be. Any help is greatly appreciated.