Botox coverage for TMJ & migraines (insurance or rebates)

I have been treated with Botox in the masseters for my TMJ and subsequent migraines for the past 5 years. I have seen a neurologist and tried a couple different medications for the migraines with no avail. I wear a night guard and see a chiropractor weekly to release the tension in my jaw, and have done so for the past few years. By far, botox in the masseters has given me the most relief. It can be quite costly and I’m curious if there is any way to reduce the cost and how to do so. Thank you!