I'm 20 yrs old (male). I have lost my hair too much in previous 1 year, now my hair falling is stopped but can I get my hair back which I have already lost?

Have you been to a dermatologist yet to find out what the reason for the hair loss was? I would recommend that as an essential first step.

Success or failure depends on what the reason was. Male pattern Baldness really has no cure despite what the infomercials trying to hawk their snake oil may claim. If the loss was for other reasons then you may find far greater success.