I callus easily, and I've had rather rough ones on my heels, big toes and on the joint below the big toe. Rough, but not very thick, so the most I'd do or have done is have them sanded down during a pedicure. I wouldn't need a razor, even if I'd allowed it (a risk for those of us with diabetes anyway.) But calluses can crack, which means the possibility of infections.
I started using the cream last night.
You can barely tell I have calluses. Already. After three applications.
I'm getting a pedicure tomorrow. This is going to be interesting.