possable syphilis aswell syphilis is misdiagnosed alot and its a round red spot .get checked.
Hello,
Without examination, confirmation of a diagnosis is tough but it can be contact dermatitis, rash due to friction rub with clothes, dermatitis (atopic, contact, allergic),excessive sweating causing sweat dermatitis, dermatitis skin or balanitis(due to an underlying infection (bacterial and fungal as well as other organisms).
I suggest you to get an evaluation done from a dermatologist to confirm the diagnosis.
I sincerely hope that helps. Take care.