At first glance, this might look like a cute picture of a squirrel loading his cheeks up with acorns. But when I downloaded the pictures, I realized that only one cheek was puffed up. That's odd. Looking closer I saw that instead of being cute and cuddly, it was a decidedly non-cute and non-cuddly fleshy growth of some kind. A tumor? It looks like it has scabs and pus on it. I suppose it could be a botfly, which I know affect squirrels in this region. Bad place for a botfly!
The growth, up close.
The non-tumor side.