It does look somewhat like frostbite, it could also possibly be burned. I know sometimes they use heat plates that go under the birds rather than over (they stand on them) and I have heard of burns from them getting too hot. I've no idea how they've been kept, so just putting that out there. It's also possible it's an injury, possible from being crushed somehow during transport or handling. So now all you can do is try to keep it clean and dry, daily soaks can help with pain and swelling. Try to make sure it can heal up without any further damage. I would be very careful about anything else, you don't want to make it worse. Wrapping the foot could help, but be very, very careful to not do it too tight. And I would check it daily, watch for any signs of worsening infection, loss of blood flow or necrosis of tissue. Those feet are so tiny, it does make it a challenge. Also make sure the chick is completely dry after soaking, so that it doesn't get chilled.