Hi there...my first thought is that this could be a localized skin infection. If this is the case you can try an antibiotic cream such as neosporin or polysporin, but she may need some antibiotics prescribed by the vet.
There are some other possibilities. It could be a parasite called Demodex, but this is much more likely in young puppies.
Is it possible she has frostbite?
There is also a condition called vasculitis which can cause strange things to happen at the ear tip, but this is quite unusual.
I would try the cream and if things aren't improving in a couple of days then a vet visit is in order.
I hope this information helps! If you have more questions, just hit reply. Or if my answer has been sufficient then please hit accept. I am in appointments today so I may not be able to respond right away. Thanks!Dr. Marie.
Veterinarian
Compassionate licensed veterinarian with >20 years experience with cats, dogs and pocket pets