Don't want to throw cold water here, but non-length dependent small fiber neuropathy definitely can affect the face. It did mine.

My above the ankle biopsy site showed not much evidence of SFN. Lower thigh showed more and high thigh showed most.

But if your docs don't think you needed the higher sites biopsied because above the ankle showed no evidence of SFN, then it's up to you whether or not you want to go with that or ask to have the other two sites done.

Sheltiemom