Hi!
In all probability you have a patch of dry scalp due to dandruff. Apply coconut oil twice a week and wash hair with anti-dandruff shampoo. For the last rinse, squeeze a lemon in a mug of water and rinse hair with that. If symptoms persist, consult a skin specialist.
Hope this helps. Take care!
The medical advice given should not be considered a substitute for medical care provided by a doctor who can examine you. The advice may not be completely correct for you as the doctor cannot examine you and does not know your complete medical history. Hence this reply to your post should only be considered as a guiding line and you must consult your doctor at the earliest for your medical problem.
Also to add, I'm 19 and have never suffered from any head injury. This has been going on (on and off) for approximately a year and a half