My lovely little boy, Chocolate, has got a bad eye. He has been like this for a few days now, at first I thought he could have caught it on something, or maybe scratched it, but now I'm thinking not. His right eye is perfectly fine, nothing wrong with it at all. His left, however, is a different story. So it's kind of swollen, it's not closed and he can still see out of it, but it's kind of puffy, his fur has fallen out in a small patch and there are tiny little scratches and scabs on the patch. Does anyone know what it might be? And how I can treat it?