

No idea if this is the right place, but any recommendations on how to repair this?
This is my almost 3 year old backpack and yesterday, I've noticed that the bottom parts here, as seen in the pictures, are rubbed open and now it looks like this.
What's the best thing I could do about this? I was thinking about just getting a thicker garn, like used for embroidery or to crochet, and basically go around it a couple times to cover it up again.