Suggest Treatment For Lesion On Face

I was diagnosed with scabies, crusted on my face. The first time I ever had a lesion on my face was at 8 yrs of age. I am now 47 yrs old. The biopsy came back PRURIGIO NODULARIS. My doc felt that it was due to a 35 yr infestation of scabies. I have had 8 weekly doses of ivermectin and only some improvement. I also used premethrin and Crotamitin Do u think this is possibly some other kind of parasite?