Hi Clover! I had this similar issue of a hard surface limp on a front paw with Jack (approx 8 or 9 at the time). I successfully removed it with pressed and sliced garlic. Patience is required by both of you as it is not an over night cure ..however i'm sure you are patient by now,especially at the young age of 8 ! :)
But before we begin, do you see any differences when you look at each pad? You should see something circular, which could be a corn.
Basically we press garlic and got the mush AND juices onto the pad. In the beginning i used those corn foam pads (for humans) and stuck them to the pad and pressed the garlic into the opening, then attached a band-aid over top to keep the garlic mush and juice in. I also used plastic wrap buy pressing the garlic onto it, then 'adhering' this onto his pad. Adhering is the fun and interesting part...think Macgyver! Try band-aiding/self adherent wrap/taping it on. It's not the easiest thing to do, but be creative and enjoy this bonding experience between you two !!! :)
Try to keep the juicy garlic to the pad, as apparently to much garlic can actually sting...so it may sting the regular skin/fur area. You can test this on yourself if you want to confirm ..just kidding.
One other side effect i noticed was Jack's pad turned PINK, like a new puppy! I was tempted to clean/disinfect all his toes!!! LOL
Best of Luck