That looks to be from wet, acidic conditions. If you had some burn cream or preperation H to gob on there and wrap with the elastic bandage stuff just for a couple days that would probably draw out a LOT of the pain and swelling. Then let them dry out. As far as his body condition, put him on some high protein feed and vitamin supplement. Dry cat or dog food will give him LOTS of protein and my turkeys LOVE, LOVE, LOVE it for a treat.