Dog facing life in a cone, possibly.

We adopted a dog over the summer and she had some skin issues when we got her. The shelter told me that she had mange when they picked her up but it was clearing up and she should be ok. She was stinky and greasy. I gave her a bath but she still smelled.

I took her to the vet and they gave me some flea /tick/ heartworm prevention that they said would also help with her skin. A month later, I took her back to the vet because her skin was still not in any better shape and they gave her an antibiotic shot and an allergy shot and a medicated shampoo to use once a week. She seemed to do better for a couple of weeks but then she started scratching. After another month had passed, I took her back for another allergy shot. She was still itchy but not so much. Then 2 more weeks passed and she really upped the scratching. It seemed like overnight she scratched her poor face raw and chewed a bald spot on her tail.

I went to the pet store and bought a cone for her to prevent further damage, took her back to the vet who gave her another antibiotic shot and to a animal dermatologist who gave her an additional prescription of oral antibiotics and fish oil to put on her food and told me to start using the medicated shampoo twice a week. She's been living in a the cone for close to 2 weeks now and I feel terrible for her but every time I take it off to give her a break, she goes back to scratching.

I've starting her in a pre- and pro-biotic from the pet store and some cbd skin recovery and anxiety treats but nothing seems to be helping with the itching. I'm really at a loss on what else I can do for her. I don't want her to have to spend her while life in a cone but I don't want her to keep tearing her skin up either. Can anyone give me any advice?