Hello, and welcome!
I'm so sorry Annie is uncomfortable and is worrying you.
From your description, it's possible that she has miliary dermatitis. This is usually caused by an allergic skin reaction to flea saliva. Even if she is an indoor only cat, she can still get fleas, brought in on humans' shoes and clothing. Since you mentioned it has been very hot and humid where you live, when this first started, fleas are much more active during that kind of weather. Here is more information:
As you can see, there can be other causes of this condition, as well, such as food allergies, mites, etc., and before treating it, the underlying condition must be found and then she will be prescribed the best treatment. It would be advisable to have her seen in person by her vet for a definite diagnosis and treatment.
For the moment, to help with the itching, you can give her an antihistamine like Chlor-trimeton--1/4 of a 4mg. tablet, every 12 hours, but always consult your vet before giving any over the counter medication because s/he knows Annie's medical history, best. As you may know, one of the side effects of antihistamines is sedation. Here is more information: Chlor-trimeton
Where she has scratched to the point of opening the skin, you can apply a thin film of plain Neosporin antibiotic ointment. If she licks it, it's not harmful.
Drs Foster and Smith make an 'Itch Stop' series of topical products which you might try: CLICK HERE
You can start her on a topical monthly flea treatment like Advantage, but again, due to her age, consult her vet, first, as some cats can have adverse reactions to flea treatments. Only use one that is sold in your vet's office or the same name brand products that are now sold in pet supply stores (like Advantage, Frontline, etc.). However, do NOT ever use Hartz, Sergeant's, Zodiac or other brands that are sold in pet stores and supermarkets, as these have proven ineffective and have caused fatal reactions in cats.
I hope all will be well with Annie and please let me know how she's doing. Thanks!
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