Try not to worry too much for now, my dog also had a small lump on one of his back legs but the vet said it's pretty normal and absolutely nothing (for that particular one). And now my dog has fully recovered.
Have some good sleep, until you are able to bring your cat to the vet after new year sin la. All the best!
Glad to know that! I think if it's not harmful at all, whether it will go away or not won't be the main concern, if your cat won't act abnormal or try to scratch it. Don't worry too much, just wait for the 4-6 weeks sin la!