@Just
I've been thinking on this and @Jynx mentioned the book that I hear lots about but haven't quite read.
I have *some* insight into the blood thing...
There are occasions where my scars itch or burn, like my body is fighting against my mind, like I need to make it stop, either the reminders or the pain. Yes it's travelled up my arms before or my eyes have suddenly started burning.
I know the seizures I have are a direct result of my mental stress, like my mind says "this is too much for you, I'm shutting down" aka a seizure.
It's a concept called psychosomatic "having physical symptoms but originating from mental or emotional causes"
I know how I stop it for me, I ground myself in this moment or I write.
I've previously been told that it's your body trying to understand or comprehend your experiences. I still get excruciating stomach pains with a particular type of memory, then I dissociate or have a seizure or flashbacks and the pain makes sense.