i just wanted to second what rosie said. self-mutilation is not a disease: it is a symptom of deep problems.
if you are vulnerable, get someone with you. my wife hired someone to watch me after my suicide attempt 6 yrs ago. the key is to stay safe. NO MATTER WHAT. if checking yourself into a hospital is the answer, then DO IT. you MUST be somewhere where you are SAFE.
if yoour pdoc has an after-hours line (most do, i understand) then call that number and tell them that you are having an emergency and MUAAT SPEAK WITH THE DR IMMEDIATELY.
gaz, please get the help you need. you have been in my thoughts and will continue to be.