It may not be sperm that's accumulating, but smegma, which is something different.
Candid B cream is an anti-fungal cream, and if your symptoms are responding to it, it means that your symptoms are being caused by a fungus, like yeast, jock itch, or another fungus. This is VERY common.
How's your hygiene? Keep the area clean and dry - don't overdo it, though. Lots of experts recommend not using soap, as that can be very drying, but a cleanser or emollient. https://www.nhs.uk/conditions/balanitis/
Balanitis can recur, especially if caused by a fungal infection. How long did you use the cream? A lot of experts recommend using it for at least a week, if not two, after symptoms have cleared to ensure that it's fully cured.
When you say you showed a picture of it to a doctor, did you ever have a doctor look at it directly? That is usually better than a picture. If what they told you to do to cure it hasn't after following directions, I'd go back to the doctor to establish a more accurate diagnosis.
I have the same problem you should see dermatologist it could be some kind of skin condition..