Thanks for posting question on HCM,
Dear this is called canities (greying of hair in young age)it is mostly genetically determined and runs in the families who marry in same clan.rarely it is because of Zinc deficiency
and few syndromes like Piebaldism
You can camoflage it by applying like Restoria dicreet lotion daily for 3 weeks .you may also take zinc and vit E supplements.
Hope this will alleviate your anxiety
Dr sher bhutto