I have ocd. I used to see someone for it....years ago.
I have mostly symmetry, some mild counting/finding patterns, and GERM issues. I used to have rituals to keep people safe. That's the thing that tipped my therapist off.
I've gotten a lot better over the years,but I still have rough times.
it's interesting that you mentioned wanting to cut your hand off. when I was a kid, if something gross got on my hand, i would just stop using it to eat or touch anything that would touch me. crazy looking back at it.i don't know how nobody noticed.