I have been taking gralise for a month and 900mg for two weeks and i'm still get headaches. what should i do?

Gralise: is a well tolerated once a day long acting form of Gabapentin. (Neurontin) It can be quite helpful in the management of neuropathic pain and often works for radicular pain. Occasionally it can be used like other anticonvulsants for migraine management. I suggest you let your doctor know you are still having headaches. Headache is usually approached as a paroxysmal disorder. (Not pain disorder)