Suggest Treatment For Scabies On My Stomach And Back

i have several spots on my stomach and back doctors says it scabies but i had scabies before and they didnt look like this..there red with dark marks in the middle and they do not itch..kinda looks like ringworms to me but they start off as a little tiny red dots then forms into big red things with black marks..been using peremthrin but it's not working!