Dog fight aftermath problems

[mittens1997]

On Saturday my girl Millie for in a dog fight with my sisters dog and walked away badly from it. We look her to the vet and she ended up getting about 20 stitches on her front leg along with two drains put in to drain out the infection. She is an outside dog, (with an insulated barn). Today we left her inside while we were out because it was her first day with her bandage off. Anyways, we had left her with her breakfast and water. We got home and most of her water was drunken but most of her food was still there. While she has never been an enthusiastic eater, normally she eats her food within the hour.

So thats a bit worrisome. Should i be concerned or nah? I let her outside after all day inside and she didn't pee or poop... and there was none inside. Also, She has to go back outside now. The vet told us she should be fine outside with her arm shaved like it is, but its still rather cold. (-25-40c ranging) Does anyone have any ideas to help her stay warm?

I crocheted her a little arm wrap, but while putting it on it kept snagging the stitches, and i didnt want it to accidentally pull some, so i opted out of that.
But still, she's cold! Does anyone have any suggestions to what i can do? It has to be open enough that her drains can still drain and not infect her stitches by draining onto them.

Thanks!