If your rose oil is a single formula, you can add it to olive oil and use it, no more than five drops if you only use it on your face. If it is a rose essential oil compound you can rub it directly on your face. They are both plant extracts and can be mixed, 1:1 is fine. There is a very good moisturizing and emollient effect. Summer skin gland secretion is more vigorous, try to use less. Because they are oily, molecular weight is also relatively large, easy to clog pores. And oil absorbs light and heat, easy to make the skin black.