there are also some dry skin on the penis head
Hi,
This could be any irritation caused by any substances encountered during swimming. Are there other signs or symptoms present? Another differential could be Fordyce spots which are small bright red or purple papules that can appear on the glans, shaft or scrotum. This usually affects younger men and may occur as solitary lesions with abnormally dilated blood vessels, covered by thickened skin. They are not infectious and their cause is unknown. If this persists, It would be best to see your doctor for proper evaluation and management.
Take care and keep us posted.