Welcome to the Dermatology Expert Forum! Thank you for your question.
It is possible that you have developed a penile irritation/inflammation around microinjury (small skin damage), probably caused by friction during intercourse and exposure to different body fluids later on. With proper hygiene and avoidance of further irritation this lesion should be gone in few days.
Other possibility could be a mild folliculitis.
I am sorry I cannot say much more, but the quality of the picture you posted is not very good, and symptoms you mentioned are rather nonspecific.
Plan of action: stop worrying, and enjoy holidays with your family! However, if new lesions appear, or existing one does not subside, seeing a dermatologist would be the best strategy.
Wishing You Optimal Health,
Dr. Jasmina Jankicevic