Wait. If it was watered too often you probably have root damage, meaning that the roots were unable to transpire water up and through the leaves. The leaves probably had severe wilt, turned a darker green color and are now turning brown and crispy. All you can do is hope the roots are able to make a comeback.. If not this then it is probably blightI have a tomato plant which had signs of over watering,didn't water for two days now it looks like its dying ,leaves turning brown.what can I do??