Welcome to the forum. Preferably he should go to the vet but if you can not do that then flush out the wound with water to clean it out. You can use neosporin (the type without pain reliever) to help prevent infection. The problem is frogs hunt their food by movement. So with one eye he is going to be at a serious disadvantage in the wild. They eat crickets and other insects. They can also eat worms but they need to move so he can see them. Are you prepared to keep a frog as a pet? If not you can nurse him back to health but he may suffer a similar fate once released. Nature is not very sympathetic to the sick or injured. If you do desire to keep him post a picture so we can help you figure out what kind of frog he is so we can offer you advice on a proper setup and care. Let us know how it goes. Good luck.