Anything that smells... No, seriously. That's the only kind of sniffing one should do. Why on earth would you ask such a question? The answer is nothing. If someone told you to go snort cocaine and...
Yes, it will still show up the same (if you live to take a test) but your body will have massive amounts of the Fentanyl in your system instead of a certain microgram per hour as the Fentanyl...