one day about 6 yrs. ago i noticed bald spots on my neck when my beard grew out a little and before i new it my mustach wasent growing back , my beard stoped growing, and my eyebrows were gone and have not been able to grow much of anything since. My eyebrows are still gone, no mustach at all and my beard is starting to come back but no color, all white and widely spaced. what are causes and can i get my hair to grow again?