Hello, my name is***** and I have over 20 years of experience as a veterinarian.
Did you mean that you applied Avon's Skin-So-Soft Bug Guard Plus?
If so this is not toxic per se. It doesn't not cause organ damage, but it is a gastrointestinal irritant.
That means if Lacey ingests the product she may drool, be nauseous, vomit, have some gastrointestinal cramping and diarrhea.
So ideally if she's a big licker I would not apply this particular product. While it won't be harmful long term, it can make her feel pretty poorly, with vomiting and diarrhea.
Instead you might bathe her with an oatmeal shampoo to soothe her skin, and follow it up with a conditioner made for dogs.
If you believe her itch is allergy based you can use a combination of antihistamines and high doses of omega-3 fatty acids to help with those. In combination fatty acids and antihistamines work synergistically to help allergic reactions, much better than either one alone.
You can try:
1)Benadryl (diphenhydramine only don't use the combination products with decongestants or acetaminophen as they can be toxic) at 1mg to 2mg per pound of body weight or one 25mg capsule per 15 to 25 pounds of body weight orally every 8 hours.
OR 2)Claritin (loratidine) at 5mg per 25 pounds of body weight once or twice daily.
OR 3)Hydroxyzine at 1mg per pound of body weight orally every 8 hours.
OR 4) Chlorpheniramine at 4mg to 8mg per dog once or twice daily.
OR 5) Zyrtec (Cetirizine hydrochloride) at 1/2 mg per pound of body weight orally every 24 hours. That would be one 10mg tablet per 20 pounds of body weight. Make sure it is NOT the formulation with a decongestant (such as Zyrtec-D) because dogs cannot tolerate decongestants.
Some dogs do better on one antihistamine rather than another.
Give the one you pick a week trial and if it isn't working try another. Be aware that antihistamines can cause sleepiness or hyperactivity in some dogs. These side effects do wear off with repeated use.
Omega-3 fatty acids are fish oil products. 3V by DVM or Derm Caps ES are good brand name products. Use the high end of the dosing schedule for your pup's weight, meaning if she is between doses, dose high. I recommend an omega 3 fatty acid dose based upon the EPA portion (eicosapentanoic acid) of the supplement as if we do that the rest of the supplement will be properly balanced. Give her 20mg of EPA per pound of body weight per day. For example an 80 pound dog could take 1600mg of EPA per day.
Please let me know if you have any further questions.