Hey Krios,
Falling out of CH remission while on the vitamin D3 regimen can happen to any of us. It happened to me in 2015 due to a pollen allergy and again in 2018 due to a mold spore allergy. We've learned a lot since then.
The winning course of action to get back CH pain free is to start loading vitamin D3 at 50,000 IU/day, ditch the Benadryl (Diphenhydramine HCL) and start taking 3 grams/day Quercetin. Quercetin is an excellent antihistamine and unlike Diphenhydramine, there's no drowsiness or time limit on dosing. Bumping the Turmeric (Curcumin) dose to 3 grams/day also helps