Will hair grow back if i stop?

Hi guys. I have an awful habit of picking my scalp! I also pick at my finger nails, and even pull at my eye lashes , eyebrows and even pubic hair but its my scalp that has recently made me wake up and realize i have to try and stop this habit!! I have always had a tight shaved head so my hair was always very short but recently i decided to leave it grow. One of the reasons being was that i thought it might help me with stopping to pick at my scalp but not only has it not helped! As it grows back i can see that my hair on top is really after thinning out! I mean its pretty noticeable and iam now worried ive done permanent damage? My dad thinks iam just going bald slowly but surely but it doesnt make sense because both my parents have full heads of hair and are in there 60s! I cant think of anyone in my family thats bald in fact so why would i be? Its got to be all this picking i have done? Question is, If i stop this now... will the hair ever grow back? I really want to leave to my hair grow but iam tempted to shave it all again to hide the way it looks Thanks to anyone that replies