If you have Morgellons, you know it is not like nothing described in medical books. It is not natural. The body has defenses against infestations of insects.
Insects don't live in human skin...
Except if they have been genetically altered to live symbiotically in the human body.
There is a type of "worm therapy" that is used to treat diseases but those aren't genetically altered worms.
Helminth Immunomodulation in Autoimmune Disease