What Causes Worm Like Sensation Under My Skin?

my mom picks at her skin thinking she is digging out worms on her arms, under her nails, and her hands. It just looks like dry skin to me. I wonder if I looked under a microscope if I could see the worms. She says she can see their head and eyes. I think she might be hallucinating. She has been to the doctor and they said it was from her lack of VB12 (hallucinations). They gave her some cream to put on her sores. This has been going on for a year.