Brief Answer:
Suggestive of mole

Detailed Answer:
Hi & Welcome to HCM.
I can understand your concern.
After having gone through the brief history given and the the uploaded picture I am of the opinion that the small black thing (encircled with black ink) that appears on the skin below the head of the penis seems to be a mole.
Mole is a benign pigmented lesions of the penis which usually appear on the shaft and/or glans (glands) of the penis.
It is usually harmless and do not requirement any treatment. But you should immediately visit doctor if you see any changes in size, color, and texture of the lesion or if you start getting itching or bleeding from the lesion.
Hope the suggestions given above would be useful.
Regards.

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Brief Answer:
It could be wart due to Molluscum contagiosum

Detailed Answer:
Dear Biswajit, Hi
Thanks for your reply.
Reviewed the uploaded picture, it seems to me it is a small swelling on the skin below the penile head with a tiny dimple in the center which could be due to a virus called Molluscum contagiosum.
Since it is a self limited condition (as it is not causing any pain, irritation or itching) treatment may be unnecessary. However, it can be treated by Cryotherapy (freezing the lesion with liquid nitrogen) or Laser therapy. I advise you to use Vitamin A containing creams like Retin-A or Adapalene gel.
Further, a second opinion of dermatologist is highly recommended.
Hope I tried to give some useful suggestions which could be helpful to you in getting the permanent solution for your problem.
Best regards.

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