Hello,
I'm sorry t hear about your Wheaten's hot spot.
Until you can get to a vet, I would keep this area clean of hair and debris, disinfected, and less itchy/ spreadable.
If you need to, clip a bit of hair nearby so it doesn't fall into this area.
I'd gently clean the spot with a betadine (iodine) diluted 1 part to 10 parts warm water. Gently dab dry. If you can get a topical antihistamine or hydrocortisone cream (they do sell some OTC in human pharmacies), this can be applied, just a thin layer. A topical antibiotic cream, like Neosporin, is ok for infected sores and warding off bacterial infections, but does nothing for the itch of the spot nor the inflammatory process and histamine release, which is what causes these.
You can also give some oral diphenhydramine (benadryl) at a dose of 1mg per pound of body weight, which can be rounded slightly up or down for easier dosing, but it may cause some drowsiness in sensitive dogs, though no need to worry if it does. It can be repeated every 12 hours.
Allergies are a common reason for hot spots to occur, and the moisture build up on skin is what eventually causes this itchy spot that turns itchy and inflamed. You may want to ask your vet about an injectable anti-inflammatory which can last for up to 6 weeks for the itching.
Make sure your dog has access to plenty of fresh water, and please don't hesitate to reply if I can help further. You will want to do your best to keep her in a cooler area, and an e-collar may be needed to prevent her further irritating this spot while it's healing.
Christine
Certified Veterinary Technician
Licensed veterinary technician (B.S. Mercy College), 10 yrs in animal medicine and training