Dandruff can be treated with lotions and shampoo (not commercial ones). Some people do have more oily scalp which cause visible flakes which we call dandruff. There are some other conditions also which can present like flaking of the scalp and have to be ruled out. Do not apply oil on scalp as it will increase the problem. You also have tropical acne on your back. Please call me or contact me with photos through online consult option for proper examination diagnosis and treatment.