Suggest Treatment To Increase Hair Growth

Sir/madam, now I am 21 year old..i didnt get hair completely since
my birth…I think I met doctor(my parents told) when I was 7 months
old,he said that hair may be come back after some years…but I ddnt get till now..and
also I ddnt meet any doctor… is it possible to know that I have hair follicles alive or not in my skin of head…does any hair oils help me to grew hair…