Suggest Treatment For Growth On Penis

my significant other developed a soft growth just below the tip of his penis. It does not hurt. It is soft in nature, no regular shape, and about1/2 inch 3/4 inch. I was reading some pages and they mention a sebaceous cyst? Would that be something to be concerned about? It mentions excessive testosterone, we were pretty active sexually over the weekend would that cause it? For about two weeks he has been taking a multipill pack from GNC that has staminol and L-arginine