I had sexual intercourse with a girl about 3 weeks ago. I noticed today that the coronal sulcus on my penis is a bit raised around the circumference of my penis but there's no swelling. It is painless and I don't see any open sores on it. Can this condition be caused by STDs or is it caused by irritation due to frequent masturbation - I have been masturbating a lot over the past two weeks. Please advice me as I'm a bit panicky at the moment. Thanks