It's actually bulging out. I wish I had a picture for it. It extends a half a inch or so more then the other eye out of his head. The frog was matured when I bought him. I am thinking your right about the water quality. I just recentally added a pretty big water section to my tank about a week or so ago and that must of some how gave him an infection. How would I go about treating this then? Thank you for your help by the way.