Do you have pictures of the cysts? do you get tiny white spheres out of the or scales with red or black dots?
Have you considered that it may be Morgellons. Pimples, cysts, crawling sensations, and food allergies sound all too familiar.
Morgellons has been reported to respond to Ivermectin but it takes much longer than Nematodes (round worms). I have noticed from reading Morgellons websites and other Morgellons forums that there are some reports of both Ivermectin and Albenzadole causing Diabetes. Morgellons Case Study by Morgellons.org reported 30% incidence of Diabetes in Morgellons suffers studied.
My current hypothesis regarding Morgellons is it is caused by a parasitic worm not a Nematode, Trematode or Cestode and a host specific Fungus. That is why I post Morgellons information on parasite Forums.