You ARE doing everything that’s possible for this kitten, so don’t beat yourself up about that, and she is so sweet, poor little thing with her eyes. Will the vet prescribe a triple antibiotic ointment for the eyes instead of drops?
The trouble with the feline herpes virus in kittens is that a kittens immune system is just not fully developed and she will have this her whole life. All my cats have it and it only flares up when they are stressed which isn’t often. But in adults you can give l-lysine (human grade, found in the OTC pharmacy section) crushed up and put on their food. It helps to boost the immune system and keep the eyes clear and help with sneezies. A small amount in her food probably won’t hurt her, but I would be more concerned about getting her eyes cleared up.
Sometimes in extreme cases, kittens eyes cannot be cleared up and they end up losing one or both. Don’t freak out, blind cats are still wonderful pets and live healthy lives once they don’t have to live with diseased eyes. I hope everything turns out for you, keep us posted!