Christmas is time to be creative. Whether it comes to making the decoration, dinner serving or even the sweater. If you got your very own design for Christmas and simply there is none like it anywhere, then just make it yourself.
You may decorate the ugly sweater from last year by adding more stuff like bells, lights, ribbons, garlands, or even led. Or if you got a grand Ugly Christmas Sweater ideas that just need to be made from scratch the, by all means, go with it. Just make sure everything is finished by Christmas.
Other people already have done this. Have a look at these pictures to prove it. If others can do it, you can too.