Face a small one with which side to sleep need to be judged according to the causes of the face a small one, in general, if the face a small one due to poor daily habits, can be a large side down to sleep, if the face a small one due to facial dysplasia, can be based on personal preferences, generally no special requirements: 1, poor habits: if non-bony factors lead to face a small one, such as Long-term keep one side of the sleeping posture or long-term use of one side of chewing food, then you can take the side sleeping posture, that is, with the face relatively larger side in the next sleep, or alternate with lying posture. At the same time should pay attention to change the opposite side chewing, and appropriate massage, long-term persistence may have a certain improvement effect; 2, face dysplasia: If the bone development is asymmetrical resulting in a large face, that is, due to bony factors, which side can sleep, because at this time the method of changing the sleeping posture usually can not change the face shape. Generally, you need to consult a dental hospital or a plastic surgery hospital to clarify the specific cause, and you may need to undergo plastic surgery to make both sides of the face the same size, such as due to overdeveloped bite muscle on one side, suffering from asymmetrical face shape, you can also choose to inject botulinum toxin to reduce the size of the bite muscle. Therefore, it is important to change sleeping position at an early age to avoid long-term pressure on one side of the face and the situation of a large and small face. If the correction is not timely and develops into a bony factor, it is more difficult or ineffective to change the sleeping position at this time, so you need to consult a doctor to choose a suitable method for improvement.