It looks like Bumblefoot. (Is it just on top?)
Since it's on top, I would try soaking in Epsom salt water. Clean well, then apply some clear iodine to the scab -cover the whole scab. Repeat the next day. Then with tweezers see if the scab will pull out with the core attached. I would wrap the foot to keep it clean/dry. Once you get the core out, apply Vetericyn or triple antibiotic ointment.
Another option would be soaking daily in Tricide Neo for 5-7minutes 2x a day.
Mix Tricide Neo at 1/2Tablespoon per 2quarts of distilled water (the mixture is good for 5days, then make new). After soaking, dry well, apply Vetericyn or triple antibiotic ointment. You can wrap the foot if you wish.
I would try either method, before attempting to "cut". Since the location is easy to monitor, hopefully you will start to see results in several days once you start treatment.
Keep us posted.