How does MB work? Need specifics plz?

My pain Dr recently told me that troches are only for cancer patients when I asked for prescription. Well I have CRPS and he’s been treating me with most recently with low dose ketamine infusions and I’ve heard about mind-bloom and joyous in this group a few times but how exactly does it work? Do I need to hook them up to my pain dr? Cuz he gets easily pissed off. I’m all for seeing a psychiatrist even if it’s over the computer but could someone please give me more details? TIA🧡