Hello, thanks for your question today! I am Dr. Drew, and I am a licensed veterinarian. I'll be happy to help you in any way I can.
Typically, dewormers will take effect within 24-48 hours,
sometimes you may see worms in the stool, which could be in the process of dying, or already dead.
some worms are too small to see.
For fleas, there are many choices.
if you are looking for products that do not require sale by a veterinarian,
then I'd suggest K9-Advantix, which provides excellent prevention against fleas and ticks, and is reasonably priced for the quality you get. It's sold at many pet shops or online.