I did this once, actually. The woman seated next to me had applied far too much perfume, and I have an allergy. Moving to an empty row in the Y+ bulkhead was my best option. I discreetly asked the F/A if I could move back, and she had no problem with it - in fact, she also ran me back drinks anyway.

I stayed there until landing, though - not sure why you'd return to F for the last few minute of the flight. Maybe baggage was stored up there or the F/A had hung the passenger's coat?

(As an aside, this is a good reminder for the community - if you like wearing perfume or cologne, please be considerate and apply it at your destination. Wearing it onboard can be a real problem for those of us who react negatively to some of the more common scent components.)