Don't toss it yet. As long as there is green, there is hope. Just plain water - fertilizer is not medicine and will cause even more stress.
For future reference, if you want to make your own Insecticidal Soap, use soap, not detergent and nothing with an added degreaser. Leave the oil out. Mix one tablespoon of SOAP (I use Castile soap) per quart of water. After you spray, rinse. I'm SO glad you didn't add peroxide.
