Facial pain and gamma knife radiosurgery

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I am one year out of my adnoid cystic carcinoma (a salivary gland cancer) treatment. I had surgury and 30 doses of radiation. About 2-3 months after the raidiation had finished, I developed this facial pain. It has been their ever since and seemed to became stronger and more frequent at times. At one year checkup, the MRI showed a bright spot at my trigenminal nerver which should be the source of my facial pain. They did not see this spot in my earlier MRI results. The doctor is not sure if this is a tumor recoccuring on the nerver, or it is some nerve inflammation caused by the radiation. They need to watch it and compare it with another MRI in 3 months. If it is a tumor recocurring, I will have to go through a Gamma Knife radiosurgery to kill it. Has anyone had the similar facial pain problem or had underwent a Gamma Knife radiosurgery?