yesterday we gave our cats Hartz flea and tick drops and they seemed fine until about an hour ago. at around two today we noticed that our younger was shaking pretty badly and we washed off the medicine as soon as we could. we looked online to see the possible causes why he was shaking so badly. our older cat who is almost 2 was doing fine but just in case i washed the medicine off as soon as we rewashed our younger cat and dried him. about 15 minutes ago we rewashed him after contacting an emergency vet and they told us to wash him again and if the shaking did not stop soon to bring him in immediatly but there wasnt much we could do if the medicine had gotten into him system. so far he is doing better but its only been about an hour and a half since the initial trembling. he can walk around and he seems to be very worried about how clean he is. he keeps trying to lick his back but i’ve been trying to keep him from it just in case we didnt get all the medication off. I’m so scared though because he is one of the best cats ever and i dont want him to get hurt or die. its been really hard to go through this not knowing if he is going to be ok. our older cat is doing just fine thankfully but its just like i sorta dont know what to do now. now our younger cat just walked by me and is sleeping in a spot of sun in the kitchen. i just hope he makes it through this.