Please help me

[born]

When i was 16 years old i didn't wash my hair often.After some months i had a very red itchy scalp and a burning sensation.My hair thinned on the mid scalp.I've gone to a dermatologist and he gave me nizoral and ketokonazole.The burning and pain went away but my hair remained thin.Now after 5 years i have exactly the same amount of hair.My hairline is strong and my crown area is also really thick.However my mid scalp (where i had the burning sensation)is still the same.What can i do?I don't think i have male pattern baldness and so does my dermatologist.If i had started thinning when i was 16 i wouldn't have much hair (21 one) without following a treatment.