Hair loss from Trichotilllomania if it does not return with minoxidil probably needs a hair transplant to get it back, but if you go that route, you have to be sure that you will never pick on the area again or hair loss will return
Hair
loss over a short period of time in a young female is probably due to telogen
effluvium. There are many different causes of telogen effluvium, including
hormonal imbalances (including thyroid), severe stress, illness, eating
disorders (including crash dieting), chronic illnesses,...
A male with hair loss at your age, is almost certainly early genetic balding. See a doctor and develop a plan that includes the proper diagnosis and treatment over the next 10 years. The earlier you start the better