Let me first ask why you are against using antianxiety medication for SHORT term use? If you or a family member suffered from panic attacks would you make them, or would you yourself suffer through them? I am all for natural remedies however, there are certain situations that call for medication. Seperation anxiety, like I've said before, is not an illness that has a quick fix to it by any means. If your dog is harming herself when you leave the house, your vet should be taking a more aggressive course. Dogs that exhibit behavior that is nonharming can benefit from behavioral altering techniques alone, but a dog with true SA requires more than that.
The purpose of the kong as it relates to seperation anxiety is that dogs do not have a concept of time. My behaviorist said that the first 20 minutes you leave the house is most crucial. If you occupy the dog for that 20 minutes, you have a better chance the dog will not be as panicked the entire time you are gone. Problem is, that when you have a dog as stressed as yours, it needs help to be able to focus on the kong. You also have to ensure that you stuff it and FREEZE it so that it takes 20 minutes to finish. Most dogs can lick the peanut butter and get the treats out in less than that. Meaning what you just did was pretty pointless. The dog also is not able to have the kong any other time then when you leave. When you arrive home, it must be taken away and put out of sight. Again, what you are doing is pointless if you leave it around all the time. It is an association with something good upon your departure.
Your dog is needlessly suffering when you leave. Dogs are not human and cannot rationalize like one. A dog that is inflictling wounds on itself needs far more than a kong. I recommend the help of a behaviorist AND the book The Dog Listener by Jan Fennell to help you get started. Good luck.