Hi I Have Had Two Small, Slightly Elevated Red Dots

Hi i have had two small, slightly elevated red dots on the head of my penis now for a few months. Every now and then one will scab up and get bigger and eventually fall off again after a month or two. I now have another small red dot on the shaft of my penis. All seem to look the same and are single dots only. About size of a pen tip. Itches occasionally and is a little sensetive. Any idea whaat it could be?