I don't recommend any of the OTC flea meds or flea collars. Know of two dogs in our area that had neurological reactions. I used to use Advantage on our cats with no problems. I now use a once a month oral med, Trifexis, with no problems. My kids have used the oral med Comfortis on their dogs for some time with no problems and good results.
As for your question, I would think it would be ok but think I would give the Vet a call and run it by them as not sure how long it stays in the system and it may be an allergic reaction.
I have noticed that many store bought flea and tick medications can cause irritation/allergic reactions (Iworked for a vet for 8 yrs). I reccomend using vet-approved meds for this, such as Frontline.
Zodiac, Sargent's and Hartz Mountain flea preparations have been implicated in the sickness and death of thousands of dogs and cats in recent years, to the extent that the FDA ordered them to remove many of their products from the shelves.
Flea and tick preventatives are one of the areas where you should NEVER try to go to a cheaper brand, since grocery store brands such as Zodiac, Sargent's and Hartz are not safe. It's just not worth the little bit of money you save on the purchase when there's such an increased risk of ending up with a very sick or possibly dead pet and, at at best, hundreds of dollars in vet bills trying to save them after using these products. It is always best to either buy these products from your vet or ask the vet which products they recommend for your pet so you can order them from an online pet pharmacy. And if you order them from an online pet pharmacy, you need to make sure they are selling the real thing and not a pirated product that could also be dangerous to your pet.
I would wash the dog as well as I could, but if it has been more than 24 hours, the most you can do now is watch for signs of toxicity, such as vomiting, not eating, lethargy, seizures, and a general appearance of not feeling well. If you notice any of these signs or get the feeling that your dog isn't feeling well, don't wait and assume they are just having an off day, get them to the vet ASAP and make sure you tell the vet which product you used on them so they can give the correct supportive care.
If you do a Google search of "Hartz Mountain, Sargent's, Zodiac products dangerous to pets" you will see just how many problems there have been with these things.