Will plan b show up in stool test a week later from taking it ?

Since plan B won't show up in a blood test, I doubt that it would show up in a stool test. A doctor won't know if you took planB unless you tell him/her.

There is no stool test for detecting intake of plan B. For healthy diet: http://www.choosemyplate.gov/., exercise 30 minutes/day, drink enough water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs. Get HPV and Covid vaccines. Wish you good health! Safe sex: https://www.hopkinsmedicine.org/health/wellness-and-prevention/safer-sex-guidelines