I'd suggest buying a anti-dandruff shampoo. The best one is Neutrogena T/gel. It looks like syrup in a bottle,and it doesn't smell nice, but its really good for dandruff, and it'll go away after a few good weeks of this stuff. You can alwasy wash your hair with regular shampoo after to make it smell better. I'd also suggest washing your hair more than once a day to try and dry the hair out. But oil might also be a result of the dandruff.