My 27 month old shih tzu is going through this now

I just read other posts. He had the flea treatment at 10 am this morning, was fine, playing with my other 5 adopted dogs. He has had over the counter flea treatments before with no side effects, nor contraindications. He just had his physical in April and is a healthy 2 year old shih tzu.  He is jumping around, whining, restless, and his nose is warm. His eyes, and gums look ok. I just bathed him and used a dishwashing detergent to get the poison off. I am waiting for his vet to call back. We will do whatever it takes to get him well. This is the only thing it could be. I have been with him all day. He is an indoor dog , has not eaten anything other than his dog food and drank water.