What is the ruling regarding the missed prayers after continuous bleeding throughout the month due to birth control injections, knowing that I used to perform ablution for each prayer without tracking the blood or changing the sanitary pad, out of ignorance of the ruling?

If the bleeding is continuous, then you are a mustahada (experiencing prolonged vaginal bleeding outside of menstruation), and you are not required to re-bandage for every prayer. If you only omitted re-bandaging, then your prayer is valid. However, if you prayed with impurity on your body or clothes, being unaware of the ruling, then many scholars obligate you to repeat the prayer, while some do not.