Not sure if it would help CH since none of the CH med’s have ever worked on my SUNCT but may be worth talking to your doctor about just in case. So my doctor put me on Olanzapine about a year or so back and it did help but really bad side effects and withdrawals you would not believe, so I stopped taking it. He came up with a new one it is called Namenda and it is for Alzheimer's but it seems to work very well for SUNCT. He started me out on 30Mlg’s a day and all the pain went away but after a month it seems my system got accustomed to it and it was not working as well. The doctor tried to give me more but the insurance would not allow it so we are fighting with them now they only want to give me 60 pills a month max and he already wrote me scripts for .5 and for 10Mlg pills just to get me to the 30Mlg a day and get around the 60 pill thing, seems the insurance does not like this much and since this medication is not meant for SUNCT or headaches they are fighting it but it really does work for me. I bumped it up when I had some spare pills for a week to 40 Mlg’s and again the pain was gone but started coming back the next week. Not sure like I said if this would help CH but may be worth a try sure helps me.