dog flea treatment and my toddler?

I have an old black lab who's usually an outside dog, but lately we've been having a few strays around, they gave him fleas, so now i have an issue. i gave him a flea treatent last night (the kind where you squeeze the gel stuff along the back), and for now he's inside.. but i'm wondering if it's going to be a problem for my 2 year old. whenever the dog is inside, my son climbs all over him gives him kisses, etc. etc... is the residue that's still on him (you can still see the line where i treated) harmful to my son at all? or should i keep him away from the dog for another day or two?