Try getting a bottle of hydrocortisone spray. Check out the link below, not endorsing this brand, just using as an example. You should be able to pick something up at the locale Petco/Petsmart. My dog sometimes used to get hotspots due to allergies.
The type of dog food she’s eating could be a contributor also. We don’t feed our dogs anything with chicken or wheat jn it. We feed our dogs the brand below and they seem to react fine with it, the price in the link below is not what we pay since we don’t buy huge bags.
Sorry about the situation you find yourself in.
Davis Hydrocortisone Spray Pets, 4 oz https://www.amazon.com/dp/B00JHPBDX2/ref=cm_sw_r_cp_api_glt_fabc_EBYX8T6HJSB1TD4TNMKB
Natural Balance Limited Ingredient Diet | Adult Grain-Free Dry Dog Food | Protein Options Include Salmon, Duck, Bison, Beef, Lamb, Venison, or Chicken https://www.amazon.com/dp/B08746LRDJ/ref=cm_sw_r_cp_api_glt_fabc_0PERMFWFSHRVN0V4KPTZ