Hi. I Had Unprotected Sex 2 Weeks Ago. The Day

Hi. I had unprotected sex 2 weeks ago. The day after I had a tiny cut underneath my penis head, within a day this cut disapeared but I am now left with a tiny (few mm) white circular ring shaped dot/spot which is only visible when I pull the skin so it's tight. The girl I have sex with has been checked since and has no STDs. I only had unprotected oral sex about 4 weeks ago with a different girl. These are the only two sexual partners I've had since I last got checked for STDs. Should I be worried? Could this be a STD from revieving oral sex?