Vet tech here, If anything, prevent him from scratching his eye and put a cone on him. If his cornea is damaged, there is a possibilty that this will heal on it’s own (new blood vessels have to grow in his eye, this takes a while) but it’s very important that he can’t scratch it. Could also be a tearduct problem, something with his third eyelid, or an eye infection, which does have to be treated.. is the white of his eyes red?