Pimple type eruption on penis could be due to local infection from bacteria or fungus. This is also common in men who are not having sex with others. We live in a country where the atmosphere is hot and humid. This causes many of us to sweat a lot and this may result in many and recurrent fungal infections.
Next Steps
Visit a dermatologist in your area and get examined. If the need be the doctor will give you some anti fungal medicines or creams which can be applied.