Fatima bint Abi Hubaish used to have bleeding in between the periods, so she asked the Prophet ﷺ about it. He replied, "The bleeding is from a blood vessel and not the menses. So give up the prayers when the (real) menses begins and when it has finished, take a bath and start praying."
أَنَّ فَاطِمَةَ بِنْتَ أَبِي حُبَيْشٍ كَانَتْ تُسْتَحَاضُ فَسَأَلَتِ النَّبِيَّ ﷺ فَقَالَ ذَلِكِ عِرْقٌ وَلَيْسَتْ بِالْحَيْضَةِ فَإِذَا أَقْبَلَتِ الْحَيْضَةُ فَدَعِي الصَّلاَةَ وَإِذَا أَدْبَرَتْ فَاغْتَسِلِي وَصَلِّي