Ouch. That looks like a pretty open wound too. I'm no expert, but there's a chance that may need a stitch to stop stuff getting in that. Maybe it wouldn't be a good idea to keep her on wood shavings at the moment, but then, i don't really know what else you could put her on which would not get into that cut. Perhaps an old towel or a big piece of material? I still reckon that you should try your hardest to get your mother to take her to the vet, good luck.