Super glue.....

I have used it on my own feet as well as my dogs. You need to hold the paw for a few minutes to let the glue set, but it creates a hard shell over any sensitive areas. I would not recommend putting it on an open abrasion, but for slices you can super glue them shut and it works real well.

Try it on your own feet if you get a bad blister or hot spot. For those not comfortable using super glue, you can fork over the big money for the surgical equivalent.. which is replacing stitches as the least invasive/scarring technique.