Dog is obsessively licking vagina!

I'm not 100% sure I'm posting this in the right board, so please let me know if this should be somewhere else.

**There is nothing medically wrong with my dog. She has been to the vet multiple times for this issue, and each and every time the vet assures us that there is no infection or medical problem they can find.**

Last year, my husband and I went on a 8-day vacation for the first time since getting our dog five years ago. We had a close friend house-sit for us to take care of our dog Ayana, our cat and our tortoise. While we were away, Ayana developed a nervous habit to help her cope: licking her genitals until they became red and inflamed. She stopped when we came home, but we took her to the vet anyway and as previously mentioned, the vet simple told us that she's an anxious dog (nothing we didn't already know) and gave us a cream just to help the inflammation. For a while, Ayana stopped that behavior. But a few months later, she started back up.

Now, nothing triggers this behavior anymore. She'll just start licking, and licking, and licking until it gets so red and swollen that we have to put a cone on her for a few days to let it heal. The vet has told us there's really nothing we can do other than keep an eye on it, but it's driving me insane! I feel horrible for her, she hates having the cone on but there's nothing else we can do when it gets so bad. She'll spend every waking moment licking her genitals when it gets to that point. She'll even hide in another room to do it in secret.

I considered training her to leave it alone, but I don't want to teach her to NOT clean herself! She needs to lick herself sometimes, I know, but not to the point that it gets.

I'm desperate for any advice you guys can offer me! Has anyone else dealt with this sort of obsessive compulsive behavior? I'm seriously open to any suggestions at this point. I don't want to keep putting a cone on my dog all the time, I hate the idea of my baby spending a chunk of her life wearing one of those!!