First of all cover her nose to prevent her from continuing to get burnt. A fly mask with a nose flap works well. If the burn is really nasty silverzine cream is excellent. If it's not too bad then good old aloe vera juice will soothe it and help heal it. When its healed there are lots of sunscreens available for animals such as Filta-clear and Sunstop. Good luck and I hope this helps!