Make sure that the you are using paraben and sulphate free, If you can, use a natural shampoo, clean your scalp, apply onion based products which includes onion black seed oil, and also onion juice as well, eat clean.
Try applying onion and aloe vera juice on your scalp and keep it for at least 30 min
And rinse your hair with shampoo
Do this everyday for the first week...and then reduce the days eventually