Thanks for the query.
Premature graying of hair is not uncommon in general population in today's world. The cause could be multi-factorial and needs to be assessed. It could be genetic, environmental, constitutional or some nutritional deficiencies. While the treatment options are limited, an attempt to prevent further graying can definitely be made. Meet a Dermatologist for better understanding and treatment plan. Hope it helps you.
The hair cycle normally consists of growing, resting and falling hairs and there is a delicate balance between these stages of hair cycle. Normally hair should re-grow but if it is not happening, you should consider seeing a dermatologist.
Further information is in the following weblink https://www.aad.org/public/diseases/hair-and-scalp-problems/hair-loss