"Confusing skin condition"

I was referred to the hospital by my doctor. I have been getting strange blisters cropping up on my body since 2013. I was given a diagnosis of a psychiatric connected disorder of self harming. I would love to know how I am doing this so I can stop. The doctor told me to stick plasters over the top and sent a plagerised diagnosis in his findings letter. I'm worried about my future as it still hasn't improved