Brief Answer:
It doesn't seem to be a serious problem, please provide more information

Detailed Answer:
Hello XXXXXXX
I have gone through your question and a photograph you have uploaded, I will definitely try to help you out in best possible way.

Here I would like more information for better assessment of the condition
Since how long you have this pimples?
Is it of constant size or progressively increasing in size?
Is there any associated problem like itching or discharge

Meanwhile maintain good hygiene by cleaning or shaving
Wash it with antiseptic solution and keep it clean
Don't manipulate or scratch until diagnosis confirmed.

Please revert back to me with these details So that I will be able to tell you more accurately.
Waiting for your reply
Best wishes

---

Brief Answer:
You may require physical examination to establish a diagnosis

Detailed Answer:
Hello
Welcome again
sudden onset such pimples might be related to certain kind of infection or an allergic reaction

You need not to worry unless it doesn't increases in size and you don't have any recent exposure to unprotected sex.

Since I can't physically examine you to get more clues so I would advise you to consult a dermatologist or veneral disease specialist for examination and investigation to rule out infection

Hope this answers your question
Please do let me know if you have any more queries
wish you good health and speedy recovery

---