as I recall... your specialist put you on Risperidone? Hate to sound like the devils advocate, but that is the #1 drug of choice to treat delusional parasitosis. I have read no applications of that medicine as an anti-parasitic.
"It is vitally important that the practitioner does not "use the delusion" to encourage the patient to accept certain treatments. While getting the patient to take a medication, such as risperidone, may help the condition, telling them that it is a medication that "kills the parasites", reinforces and validates the delusion. Even giving the patient a course of topical permethrin "just in case" may strengthen the delusion and make it that much more difficult later on. Every DP patient can recount the visit on which his or her suspicions of infestation were "confirmed."