Is purification (ghusl) required if dryness is observed in the area of menstruation, and then light brown discharge appears after a period of doubt?

A woman afflicted with waswas (obsessive whisperings) should disregard them. A menstruating woman becomes pure by dryness (jufūf) or the white discharge (al-qaṣṣah al-bayḍāʾ). As soon as she sees either of these two signs, her menstrual period has ended, and she must perform ghusl (ritual bath) and pray. If the bleeding stops and she sees complete dryness before the usual days of her period are over, she must perform ghusl and pray, based on the saying of Ibn Abbas: "It is not permissible for her, if she sees purity for even an hour, except that she performs ghusl." Yellowish or brownish discharge after confirmed purity is not considered anything and does not affect purity. However, if it appears before dryness or the white discharge, then it is considered menstruation. Not confirming purity before performing istinjāʾ (cleaning after relieving oneself) carries no sin.