Hi Mummy I have followed your posts and just wanted to add a bit of my advice.
You have said that you have removed the implements that your DD uses to SH. My advice is don't - these items are highly significant and offer security and a degree of comfort to your DD. I learn't this through bitter experience with my own DD.
My DD started SH at the age of 16 and had a secret "stash" of instruments that she would use to cut herself (usually shards of broken glass and some stanley knife blades that she took from our tool box).
Like you I hated this and so I decided to remove all of these implements as well as hiding the sharpest kitchen knives and locking away all medication in a padlocked trunk. This was a very negative exercise as it took away my daughters feeling of control and it made her find other, less hygienic, methods to cut herself. She removed the retaining screws in pencil sharpeners to get at the blades, she found a sharp piece of stone/flint in the front garden gravel which was sharp enough to cut herself with. As a last resort she also chewed the plastic which is wrapped around the ends of shoelaces - this flattened the plastic and made it sharp enough to cut with.
When I saw the levels that DD would go to to cut herself and obtain the relief that she needed I relented and, I allowed her access to sterile razor blades along with antibacterial wipes and steristrips which she could use to pull the wound edges together afterwards,
As a mother these actions absolutely broke me but I stand by my actions. DD was going to cut herself regardless, it was my role to keep her as safe as I could and help her when she inevitably hit rock bottom after the initial cutting euphoria had subsided.
Please think carefully about the fact that you have taken your DD "comfort blanket" away. I fully understand why you would do it (I'm hardly "Mother of the Year" for given my DD cutting blades am I!) but please see it from her point of view.
If you follow my actions and give her blades/anti bac wipes and wound dressings tell her that you understand why she needs them. Explain you hate the fact that she needs to do it but remind her that you'll do anything in the world to keep her as safe as you can.
My DD is 20yrs old now and still SHs but the episodes are less - sadly I still cry myself to sleep a lot of the time so I can understand some of what you are going through.
Please look after yourself.