Hlo Sir I Am A Very Much Worried Guy ...

Hlo sir
I am a very much worried guy ... just like a six week a ago i had done the protected vaginal sex but while after taking out my penis it came out naked.. I am feeling very much worried after 5 weeks of my exposure a pimple like thing came on the foreskin of my penis . which is not open and skinny in colour.. yesterday I tested both VDRL and TPHA which came out negative .. those tests are accurate or not doctor... I am a 20 years old guy... I dont know what to do .. I am feeling very much worried please doc help me out ..Thank you very much