Penile Problems - Alrighty. I'm seventeen and I've only been ually active with one girl?

She was tested and the results came back negative. Around this time I noticed a bump on the shaft of my (that's the reason I wanted her to get tested). after a few days the bump disappeared. About a month later (now) my began to itch. As the next few days ped, it became itchier and it began to swell and turn red. Today, it spread to the entire bottom of my shaft and the area on the shaft connecting to the head. There are also a few pink blemishes around the shaft where it connects to the head. I'm thinking I should wait it out. Any ideas? I know I can't be diagnosed over the internet but I would like to see what I should expect.