Well, if you eat some really salty things, it might make you temporarily retain some water and that would show up on your weigh in. But if you keep drinking your water, you will flush it out, so no long-term harm to your weight loss. If I know I've eaten something salty and the scale doesn't go down the way I'd hoped, I just figure I'm a little puffy, but it all works out eventually.
Life's a journey, not a destination.
It's easier to stay on plan than to get back on plan.