Burning with discharge

[otherone]

Hi. I'm a 26 yr old male. I've recently used a public toilet and have developed some symptoms. At first, I felt a burning at the tip of my penis, then I noticed darker coloration running from the opening at the tip and down. Other than that, it looks normal. The burning doesn't really stop, but it does get better. It got better after a 1200 mg dose of azithromycin (but that hasn't cured it), and it usually feels better in the morning. It doesn't feel worse during or immediately after urination or ejaculation, but it did feel worse after I took a shower and cleaned the tip by rubbing soap into it. It's the same soap I've always used (Dove Sensitive Skin Unscented), and it never caused any problems. It also felt worse when I wore tighter underwear. A few days after I used the public restroom, I would also feel wetness like there was a discharge, but I assumed it must have been clear. However, I noticed a red spot in my underwear one day. The discharge has seemingly gone away as it hasn't happened again. The burning persists though. What is this?

[otherone]

Bump.