How To Treat Cracks On The Penis Head?

i am 15, 6 feet tall, and about 150 pounds my penis seems to be in bad condition. i am circumsized and the head has been getting worse for a while now, it seems that when i masturbate, its condition gets worse it has cracks and when i walk it rubs against my underwear sometimes and is uncomfortable. there is no pain. i take a shower everyday. i have masturbated less after observing this problem. it gets better when i dont masturbate. and i also started using this moisturizer cetaphil which seems to help. i dont use any other soaps or anything on my penis. i drink a good amount of water each day (about 4 water bottles). i am not sexually active. one time i was at the beach and i got this pain on the head of my penis when i was in the ocean, i washed it when i got home and that made it better. is this a problem? how can i solve it?