Penis itching and pimple type problem from last 2 to 3 weeks

i m 18 years old and from last two weeks there is itching on my penis (top side) and there is also something like pimple but they are not pimples n when i itch my penis from top i fell just as its going to discharge but it does not happen…its all 1st time with me …what to do …any treatment…???

Send a pic.

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please whats that? its been close to 4 months i had sex now. the big black spot stings me and itch