What Does A Burning Sensation In The Penis After Unprotected Sex Indicate?

Like an idiot, I had unprotected sex with a girl I didn t know. About 10-15 days later I began to get a burning sensation in my penis. I can t tell if it s on the tip, on the head, or inside the urethra. The burning comes and goes and is never actually painful. Just concerning because of it s presence. I d say I can feel the burning about 20%-40% of the time... then it drops off. I have absolutely no discomfort or burning whilst urinating. I opened up the opening to my urethra and noticed the skin in there is a dark purple. No idea if that s how it s meant to look. I had some old antibiotics from a throat infection which I took in one hit, thinking it might be Gonorrhea or Chlamydia. No effect. I m about to get tested tomorrow. My main thoughts and concerns are: - Yeast Infection? - UTI? - Chlamydia? - Gonorrhea? - Herpes/Genital Warts? - Trichomoniasis?