Hello and welcome to healthcaremagic Instead of a multivitamin, I would suggest you to take specific treatment for your acne and dandruff. A 2% ketoconazole antidandruff shampoo for scalp wash, every alternate day for 2-4 weeks should be effective for mild to moderate dandruff. Since dandruff is bound to recur again, therefore it should be followed by once or twice weekly use for maintenance. However, is using a shampoo alone proves insufficient, you would benefit from using a topical steroid solution at the scalp skin, once or twice daily along with an antidandruff shampoo. Steroid lotion can be stopped once your dandruff is relieved, thereafter you may continue with the shampoo for maintenance. For acne I would suggest that you apply topical benzoyl peroxide gel or clindamycin gel for day time use and topical adapalene gel at night time, after throughly washing the face with a gentle cleanser e.g cetaphil cleansing lotion regards