Hello everyone. I am just new here. I hope someone would help me. I recently had an unprotected oral sex 4 days ago. After a day or two, I noticed that my penis head pain and when I checked on it, I noticed a scar/scratch like mark near the tip. I didn't have any discharge nor it feels burning when urinating. I continue to monitor my situation by ejaculating to see if there are any changes in my semen, but fortunately there is none. However, I begin to be worried because I'm afraid that I contacted a STD, but she was my sex partner for 3 years and this is the first time it happened. I can still feel the pain and I really need some help.
Please tell me what might be the cause of this and what should I do. Thanks.