Hi, my girlfriend and I had unprotected sex two days ago. I am 20 years old. Later on during the day, tiny small reddish spots appeared on my penis head and made my penis itchy. The next day, it was gone in the evening but the reddish spots are still there and there is an odor. When I talked to my girlfriend, she said she had felt itchy too. What is going on and should I be worried?