I believe i have a yeast infection. i've been on monistat 7 for three days and the burning and itching hasn't gotten any better. what should i do?

Something else ?: May be not yeast infection , something else. See your doctor for an evaluation.

Need a diagnosis : Empirical arbitrary “trial” treatment for suspected but not confirmed “yeast infection” with Monistat 7 may or may not always work. If “the burning and itching has not gotten better” it may be best to seek a Gyn consultation to rule out other cause (s) of your symptoms.(like a combined infection, incomplete treatment, resistance to Monistat, non-microbial vulvovaginitis, diabetes...)