I am sorry you are going through this.
I was doing a trial of Haldol last year and had severe dystonia which was relieved with Benadryl. I imagine you've already tried this.
I used the liquid so I could titrate the dose, keeping it as low as possible while still giving me relief.
I am not a doctor, obviously; so, please check with your doctor and/or pharmacist.
Please also check for med interactions if/when choosing an over-the-counter remedy.
I hope you get some good news soon!

WC