What Causes Growth Of Grey Hairs On Genitals?

Good After Noon, i m doing job in abu dhabi, my age is 25 years old my head hairs beard dari) shave face and above penis side so many grey hairs are growing already grown i m very anxious i daily shave it for hidding grey hairs in my face i want the solution how can grey hairs convert to black hairs what should i do ? any oil any foods diet and any things i used to masturbation and handpractice and waste mony alot in very teen age now give any solution what oil do u recommand as make solution of Grey hairs please help me out