Is doubt about the presence of something on the body after ghusl due to Waswasah (obsessive doubt), and is it permissible to consider that thing as having appeared after ghusl to overcome Waswasah?

"Obsessive whispering (waswasa) is a great evil, and its cure lies in ignoring it. As for anything found on the body that prevents water from reaching the skin after performing ablution (wudu') or ritual purification (ghusl), if it is probable that it appeared after the purification, then the purification is not invalidated, and it is considered to have occurred afterwards. This is because the default assumption is that it was not present before it, similar to someone who finds a wet dream (ihtilam) but does not remember its time, so it is attributed to the last sleep he had."