I agree that it looks like extreme frostbite. Webs will not grow back. Depending how deeply the tissue is damaged she may or may not lose toes entirely. Your biggest issue is going to be watching for signs of infection. Infection could go systemic and if it develops I would highly recommend a vet for antibiotics. Also with frostbite it is crucial not to allow her back in cold temperatures until fully healed or the problem can be made worse.