Honestly I don't think that can be fixed unless cut by a vet but I can be wrong about that but it seems like that tail has stuck sheds on it but I can't zoom in on the picture and it also seems like he is in shed but the last day or soo of shed do to the darkness and color of the skin it looks like it's a day or too from shedding but again I can be wrong but I'd keep the humidity up and bath once a week maybe twice for a few months and see what happens I've honestly never seen this kind of injury besides a tiny tail kink but most breeders cut that

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