Suddenly, the left side of the face has vague pain: 1, the performance of peripheral facial neuritis, the patient is mostly due to cold or cold after the left facial nerve damage, manifested as facial nerve edema, the patient can appear the left side of the vague pain, with the development of the patient can appear the left side of the facial nerve function is impaired, manifested as facial muscle inactivity, etc. 2, some patients with trigeminal neuralgia relapse, mostly due to rest or emotional tension, the patient appears trigeminal neuralgia relapse, if necessary, give the patient carbamazepine or pain medication. If necessary, patients should be given carbamazepine or pain medication. 3. Cerebrovascular diseases, especially thalamic lesions, patients can have vague pain on the left side of the face, and in severe cases, there is also abnormal sensation on the left side of the body.