I am 21 yrs old n suffering from dandruff,it s in my scalp.what i'll do

As dandruff can have many causes and come in many forms, the solution most likely will not be an easy one step quick fix. Dandruff can have a number of causes; most common are use of bad hair products, lack of sleep, hot, dry environments, heredity, and malnutrition. Contrary to popular belief dandruff is not only caused by having a dry scalp, those with oily scalps can have dandruff as well.
Seborrheic dermatitis can be another cause of dandruff and is actually a fungus called Malassezia. This type can affect the face and shoulders as well, but not always. This type of dandruff has been commonly referred to as cradle cap, and often seen on the scalp of a baby. It often causes a red or pink area with flaky dry skin cells in excess. It can be very irritating and itchy. Many adults suffer from this type as well.
Please don’t take offence but there have been many cases when lice were mistaken for dandruff. If your symptoms have just suddenly appeared, then please have a trusted friend or family member have a closer look. Lice eggs (nits) will appear to be small and white or silvery looking and cling to the hair follicle. Whereas dandruff will more than likely have flakes that will actually fall off on to shoulders or clothing. It will appear as though it is dry skin flaking off. Either one will be itchy.
Now let’s try to help you out with a couple of remedies. Tea tree oil has natural anti fungal traits and has shown to be one of many effective methods. Apple Cider Vinegar used as a rinse after shampooing with a good quality natural shampoo is a well known remedy. You can try rubbing Aloe Vera gel onto the scalp (leave it on for twenty minutes then rinse it out). Fish oils and Omega-3 acids along with the tea tree oil have been known to be helpful with Seborrheic dermatitis. I have also heard of using an anti bacterial mouthwash as a rinse and leaving on for 20 to 30 minutes to help with bacterial types of dandruff.
All of the above mentioned methods have been known to be very effective in treating dandruff, but you must be sure to find the one that is most suits the severity of your dandruff.
Remember dandruff doesn’t happen overnight, and it won’t leave that way either. Try and pick the one you may think will help your particular type of dandruff and stick with it at least 3 -4 weeks to determine if it is effective. Good luck to you.