To be honest, ( I have a cat with allergies) I have not found anything topical that helps the itching. I think I tried everything on the market too. The only time he stopped itching is when I did the allergy testing, and got the food right.
If the scratching has been going on, there may be a secondary bacterial infection that could cause some persistant itching. For this, you could ask for vet for a shampoo to help.
Meanwhile to help the scabs heal you could make her a collar out of a two inch wide piece of cardboard (cereal packet is good) with holes in the ends and tie it round her neck with some ribbon. It tears off easily if it is caught, but prevents scratching, and cats don't seem to mind it like they do an E collar.
At first I thought it would be irritating for her if she can't scratch, but then I think about how when humans have mosquito bites or other irritations - the worst thing to do is scratch it! Thanks for this advice.
My cat has had problems in the past, always same time of year and seems to be allergy related. We shampoo her with a hydocortizone shampoo and she don's a lovely pair of "jammas" until she is all healed. Works every time for her. She's done it three times since I've had her. we bought the shampoo over the counter, at the dollar store if I emember correctly but I have seen it at Walmart too. Hertz makes it.
I've found that a sweatshirt sleeve of a used shirt cut off at the sholder, works beautifully. You cut holes for her front legs, and shorten it enough for it to go to the tail but not touching. The cuff is perfect size to keep the "jammas" on the cat and not contrict breathing. My cat has had two different pairs of "jammas" and both were very comfortable for her and didn't restrict movement at all.