Damn, I wish there was something I was able to suggest to help you, but it sounds like you're doing the things I would have already done. There is an old Bio Feedback technique that may or may not be of some help, fill your Sink, kitchen or bathroom, with as cold of water as you can stand, use ice cubes if you don't think it is cold enough, then place your hands all the way into the water concentrating on the pain in your head trickling down into your hands, keep them there as long as you can. I would have a second person there with you to help you, like if you hey light headed or something. Originally this was also used for nausea as well, so hands in until you feel as of it is working, giving you some relief, or your hands get too damn cold, so you pull them out. In the latter case, you wouldn't need an ice pack for a few mins until your hands thaw out. Yes, I am of Irish Extraction, looking for that Rainbow on either side.
Keep in mind, I read the book containing this back in the late 1980's, so bits of it are a wee bit fuzzy. I do know the party about Nasesu works like a charm.
This book taught me how to relax my body so well that I can still fall asleep anywhere, anytime, anyplace, such as the MRI Machine. The louder the noise and more regular the noise, the quicker I fall asleep, I go into REM Sleep extremely fast, and I am a Lucid Dreamer.