In 3 weeks that vet should of addressed all your concerns and explained every step of what she has done and what you are seeing. She hasn't, busy does not mean she is a great vet. Your concerns have not been met, your animal is in worse shape then before you brought it in. And that eye looks ulcerated to me and I am no expert. You leave that eye like that and you will have a one eyed cat.
I think you are doing the right thing going to a new vet ASAP. My above statement was just to second everything you have been feeling and what everyone is saying.
Please update us thanks