My mom is scratching face and in denial she is doing it. How can we stop her?

I am following this post as my own mom does the same thing. The worst thing is she has to have spots removed that are precancerous but then forgets it was done and picks and scratches those areas. How can ANYTHING HEAL?? 97yroldmom, I appreciate your suggestions! Hope others will contribute to the conversation as well.

My aunt was/is scratching her nose. Her dr told me to put a bandaid on and see if it healed. She thought it might be skin cancer. I didn't think so but went along. It healed fine in a few days. She also had me use a hydrocortisone cream on her arms and legs where she scratched. It wasn't long before she had her nose red again. I just tell her aid to put a bandaid on when she breaks the skin. The bandaid helps her to he conscious of what she is doing. I realize this might not work at every stage but it is working now.
I also keep her fingernails clipped.
The aid also has her put cream on her arms and legs each morning. She puts her hand out, the aid puts the lotion in her hand and she rubs it into her skin. Again, at some point I'm sure she will need the aid to apply it but for now it works.
So instead of scratching and picking she is moisturizing.
It doesn't stop what happens later in the day when the aid isn't there but at least we keep on top of the situation daily.