After the initial surgery of oral and maxillofacial malignant tumors, it is very crucial to prevent recurrence, especially local recurrence. However, due to the different living environment of tumor patients, tumor types and sensitivity to postoperative adjuvant therapy, moreover, due to the biological characteristics of malignant tumors that are prone to recurrence, it is still difficult to prevent their recurrence completely by existing medical means. However, with the improvement of medical technology, tumors can still be controlled or even cured again in the early stage of recurrence. How to detect the recurrence of tumor in early stage? Doing timely self-examination is the key. First of all, I would like to introduce a case: an elderly patient in his eighties had undergone extended resection and radical cervical lymph node dissection for submandibular gland hypofractionated mucous epidermis-like carcinoma 3 years ago, followed by sufficient dose of local radiation therapy. However, just 1 month ago, he suddenly felt a mass in the sub-chin area on the same side of the last lesion area, which was just half the size of a peanut rice, with a hard texture and inactive. He came to me for a look. After examination, he was immediately asked to be referred to our department for treatment. At first he was hesitant and wanted to observe it for a while, but after my insistence, he agreed to be transferred to our department for surgery. During surgery, only a hard mass about the size of a green bean was found at the muscle attachment of the chin, and the pathological examination result was low differentiated carcinoma. The pathological examination result was hypofractionated carcinoma. Immediately afterwards, local enlargement resection and radioactive particle implantation were performed, and no cancer cells were found in the cut edge during surgery. Timely detection and treatment gave this patient another chance to be cured. From this case, we can see that even though many patients can achieve regular review, it is only relative. Because, tumor may also occur at any time during the interval of review. Therefore, patients must pay attention to the daily self-examination after surgery, and should seek medical consultation in time once they find abnormal conditions, and should not relax and delay the treatment.