Is it because there are demodex on your face that you often get pimples in winter?

Maybe it's because of the cold weather. Your body or face is a little messy, so you are willing to take oil, because your acne is mainly caused by oily skin, not by mites. Only oily skin will grow mites. If you want to control it, buy a suitable facial cleanser to control oil and acne, and then don't eat spicy and irritating food. Don't stay up late at night, your diet will be relieved.