Is she soaking the feet before doing any treatments? That softens them a bit but that skin is tough and thankfully so in any other situation, but that can make treating for bumblefoot a job. Do you have any new pictures since she's started treatment? You're right, getting on top of that infection and then destroying it completely is necessary or this will continue to flare up and become a problem over and over and over. I know this cycle all too well. You don't want that infection getting to the bone. I found that using a scalpel wouldn't work very well. It was an actual single use sterile scalpel but it just didn't seem as sharp as what you'd find in a surgical suite. I had to use a box cutter and sanitized it thoroughly. Also, is she keeping her foot wrapped or covered somehow? I felt like this was an important part of treatment. Other treatments, like using tricide-neo have shown to be less invasive, but I don't have personal experience with it. You can find lots of information on it here in BYC using the search function and typing in "tricide neo bumblefoot" or other similar wordings.