What can be the reason for pain while resting or sleeping on the left side of the face of a boy after surgical removal of his left salivary gland, which had a tumor?

Hello doctor,

My nephew had a tumor on the left side of his face in the submandibular gland region eight months back. He visited a nearby clinic, where the doctor advised FNAC for the tumor. After reviewing the biopsy reports, he advised him to take some antibiotics, he developed an intolerance to those medications, and his abdomen got upset. Then, he did not take any medications and was confused regarding the tumor. Subsequently, he developed pain in that region which seemed like dental pain, for which he visited a dentist. But the dentist found nothing abnormal related to that pain. Then he was advised to take a second FNAC for the same tumor from another laboratory, and the doctor suggested removing the submandibular gland. But few doctors had different opinions regarding the FNAC results. So, I took him to two to three ENT specialists and head and neck surgeons. They prescribed Augmentin for five days to see whether there was any change in the size of the tumor. During this period, the pain subsided, and a slight reduction in the tumor size was also noted. The doctor advised us to go home and come back after 15 days. We said that it is not possible as we are coming from a far place. Then he suggested repeating the FNAC, but the reports were inconclusive. He finally wanted to operate and take an excisional biopsy to know the final diagnosis as it was slightly doubtful of cancer. Then, I took him to some other doctor, he operated on the tumor, and a frozen biopsy was taken. They found that it is an inflammatory lesion and not of malignant nature. It was severely infected, so they had to remove the entire submandibular gland. After surgery, they insisted as he may develop some paralytic effect on his left lip and cheek which will become normal after a period of time. After some days, we found that he has a big-sized lesion in his parotid gland through MRI. FNAC was performed and found that there is nothing serious, and they asked us to do a follow-up periodically. Five weeks back, he developed pain at night, which settled down after taking Zerodol-P. He says that the frequency and the intensity of this neurological type of pain increase when he is at rest or sleeping, but he cannot feel the pain when he is working or driving. One more thing to add is that he had a Vitamin B-12 deficiency for which he took Magneuron OD for a few days and discontinued it without any medical advice. And the dentist whom we visited before his surgery did root canal treatment in the tooth near the area where he had pain, and he said that it looked like a neuralgia type of pain and did not look like pain due to dental cause. For which treatments like hot water compression and a single dose of Zerodol-P would help? Kindly advise us regarding what you think about this sharp pain that subsides with a single dose of Zerodol-P and again recurs in two to three days. Help us by suggesting some solution.

Thank you.

Thank you doctor,

Kindly note that the operated lesion was on the left side only, and he is getting pain in the left lower lips which radiate to the lower dental area. Now he has another lesion in the parotid gland area, as you can see in MRI. His biopsy report suggested "acute suppurative and xanthomatous sialadenitis." We are not finding any symptoms of Koch's disease. Further, his pain comes suddenly at night, and after taking pain killer, it goes in half an hour. One day he is fine, and again he gets pain only at night time. He says while resting and sleeping, pain, is more, but he feels less pain when he is working and driving. With this information, kindly guide us with what has to be done next.

Thank you.