He's not chewing on it. It started as a small eruption on his foot and has spread to what you see now with a good bit of swelling as well over about three months.
Not that expensive - it's just that we went from a six figure income home to a no income home. We have no money.
In the pictures the lesion appears to be a malignant/aggressive tumor.
Mast cell tumors and fibrosarcomas can appear as this.
A biopsy is needed.
That looks very sore and severe. Reminds me of an animal chewing on their foot. Has he been chewing on it? Have you tried putting a victorian collar on him to keep his mouth away from the wound?
I know medical treatment is expensive but if you don't get it under control soon, I worry about infection in the wound and possibly going to the bone and septicemia.
http://i170.photobucket.com/albums/u278/Geno_022/P5120086.jpg
http://i170.photobucket.com/albums/u278/Geno_022/P5120094.jpg