I search from the web got some information my help:
"A bald patch above the nose is often the result of over-grooming due to illness: the baldness happens when a rabbit is constantly bring their paws up onto their nose area because of nasal irritation (caused by illness, like snuffles or another respiratory infection; or dental disease, where the rabbit's teeth have grown up into the nasal passages; or some other problem.) Another cause can be mites or another parasite.
If your rabbit has baldness, you should bring her to a vet who has experience and knowledge in rabbits (not all vets do).