我应该只在北京28网站官方上或头皮上申请吗？
it's best to check the product description. there are some heavier oils that can be applied to the scalp, while the lighter oils should be applied only in the hair.
if the oil you're using is natural or organic, you can leave it on without any worry. the longer the oil is left on the hair, the more time all nourishing substances have to penetrate the hair.