What is it on the penis? Is it rash one by one? What rash
If this rash has obvious pain or itching symptoms, it should still have a form of eczema. However, if there is no obvious pain, herpes should be considered, so you need to do a herpes virus test.
The pictures you took show that it may be caused by eczema, stimulated by some substances at ordinary times, or caused by the unclean sanitation of the perineum. Therefore, you should wash the perineum with clean water every day, including the genitals and foreskin, and change clean and breathable underwear frequently. If necessary, you can smear dermatitis flat to effectively control the symptoms of the disease.
The granular substances on the penis epidermis are sebaceous cysts, which are generally related to not paying attention and maintaining hygiene, ventilation and dryness. At ordinary times, we must pay attention to removing these causes. These sebaceous cysts will not affect anything and do not need treatment. It's like the goose bumps on someone's arm