depending on how long you have had PN an emg can show up negative because not enough damage has been done yet to show up on that test. If your symptoms continue you might want to repeat that test in another year or so and see if something shows then.

For the skin biopsy as Glenn has posted unless you are within a certain percent tile it is not considered Small fiber neuropathy yet. Again it may take a while to show enough damage to be considered a positive test.

Just something to keep in the back of your mind for the future.