I'm so sorry you're struggling with this.

In regards to your Mom's skin picking, it sounds more like symptoms of Morgellon's Disease than typical dermatillomania. Might research that, and even show your Mom what you've found and maybe that will convince her to get some help.

The reality is that unless you can convince her to seek treatment, there's not a whole lot you can do. Be understanding of her issues, don't shame her for them. Maybe you can look up therapists in your area that might be able to help her, so that you could give her a list of choices.