Pain under the left eye

Hi,

My husband had chemo 2 yrs. ago for colon cancer. One of the drugs was Zeloda and I cannot remember the IV chemo he got in the clinic once a week for six mos. Now my husband is suffering from excruciating pains on the lower part of his eyes. Pain killers does not help much. He was seen by a neurologist and he prescribed Carbamazepine. The effect is very little. Has anybody have any suggestion

                                                      Thanks,

                                                            Evelyn.