pinworms

Sarah • 27. Married. My son was born 2/22/16 and his little sister 7/5/17
My one year old had a 3 hour play date with a little girl who just tested positive for them/ our son hasn't shown any signs but of course I am so freaking paranoid... his dr said just to check stool for the next few weeks, it's been 2 weeks since the play date, would symptoms have appears by now? Other than checking stool and anus what should we watch for?