I have had a facial rash (chin and near nose) for 5 months

I have had a facial rash for 5 months.  i have been treated with hydrocortisones with no effect and now elidel it has gotten worse.  My dermatologist did a punch biopsy and said it came back with no results.  so bascially i have a rash that wont go away and it isnt a yeast, isnt fungal, it isnt bacterial he said it wasnt cancer and it wasnt TB...so what is it?  last visit he told me if elidel didnt work he'd bring in the "big guns"  what does that mean?  do you have any idea what kind of treatment will get rid of a rash that has no apparent cause?  HELP.  it is red and bumpy and itchy and ugly!