Over the past few years I have noticed a single painless white head in the same area of my penis shaft. It is on the left middle side of the front of my penis. Does not hurt at all and shows up anywhere from once a year to 3 times a year. It shows up over night and when i pop it it is gone in 2 to 3 days. Only thing remaining is what looks like a blackhead hole. I am getting tested tomorrow just to be sure and always practice safe sex. My past gf of 2 years was clean and the new girl I am dating was tested 2 weeks ago and also is clean. Any idea what this can be?