Hello, about a week ago I noticed what looked like a pimple on the left side of the head on my penis. It has not grown in size or scabbed in any way. I have been more active exercise wise and it appears to look like just a blemish. It is a slightly darker red then the rest of my skin and is barely raised. It resembles more of a bug bite then anything. I have a long term girlfriend and we use protection 99% of the time . is there need to worry or is this a common occurrence?