Brief Answer:
Possibly a friction blister

Detailed Answer:
Hello Mr XXXXXXX How are you? Thanks for writing into HCM. My name is Dr Suresh Raghavaiah. I am a surgical gastroenterologist and I hope to answer your question today.
First of all I dont think there is anything to worry about. By the things you have shared with us, I believe you are having issues related to increased friction during sex. The black spots sound like echymotic spots (small pin point bleeeding spots), one of which has enlarged to become a blister.
Echymotic spots are very common on the penis especially after vigorous masturbation or sex. I have seen many newly weds with the same issues. It is even more common if sex was attempted without sufficient lubrication as this increases the friction on the penis.
I would not be too worried about the blood blister. Let it heal by itself. It usually takes about a week for the epithelium to grow back underneath the blister and the blister then usually falls off by itself. Make sure to retract your foreskin (if not circumcised) everyday and clean it during your bath. Also apply nystatin cream once a day to prevent infection.
You should also take precautions - Use lubrication during intercourse to decrease the friction or you could use a condom.
If none of these measures help, or if you feel the blister is increasing in size or if you develop any new symptoms, please contact a urologist immediately.

Hope this helps and hope you start to feel better. Please do not hesitate to contact me for further clarifications.
Have a great day

Dr Suresh

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Brief Answer:
Blister

Detailed Answer:
Hello Mr XXXXXXX
Thank you for getting back to me. I understand your apprehension.
I was talking about how the blisters develop. In the initial stages there might just be pin point sized bleeding which appear as red spots at first and as the blood dries up turns black in colour. Blisters on the other hand usually become big (just like you said, as big as a shirt button). But both heal the same way. The blood will get eventually absorbed by itself or the blister might break after the underlying mucosa has healed well.
Either way I don t see any reason for concern, especially if there is no pain, fever or any new symptoms.

Please do keep me posted regarding your progress.

Dr Suresh raghavaiah

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Brief Answer:
Glans Penis

Detailed Answer:
Hello Mr XXXXXXX
Thanks again for getting back to me. The foreskin is a very elastic structure and hence very rarely develops any injury. All the conditions I am talking about appears on the mucosa of the glans penis (Head of the penis). So I do understand that the blister is on the head of your penis. My advise will stay the same.

Dr Suresh Raghavaiah

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