Question: How long will the stickiness last?

First off, please let me say that thank God for this site.

I had gotten worried that my cats would get fleas because a friend of mine had a cat with fleas and I thought that I might bring them home. So, as a preventive measure, I bought some Hartz ultra guard and put it on my kitties (Baby and Tiny, 2 and 1 years old). They started licking themselves a lot and I got worried, so I googled Hartz and found this site. Immediately, I called the vet and was told to wash the cats with Dawn - which I did and very well, too, they smelled great and I helped them dry and comb their fur for about an hour, but I was so distraught that I had to stay awake all night and make sure that they didn’t have any strange shaking or movements and that they were acting normal.

Today (day after), I took them to the vet just because i couldn’t stay home and watch them all day. They didn’t do anything strange at the vet (in boarding) and I brought them home this afternoon.

The only thing weird and the question I have is:

The place on the back of their neck where I had put the Hartz and then washed it off is still sticky looking, but not feeling. Should I bathe my cats again? I don’t want them to lick any of it up again, though I thought the big washing with dawn got it all off…

What should I do?