What is the ruling on someone who forgot the number of days they intended to make up from Ramadan, and whether they made them up or not?

A fasting person is permitted to perform ghusl (ritual bath). However, if water reaches their throat during ghusl, their fast is invalidated, and they are required to make up that day, according to the Maliki and Hanbali schools of thought. As for water reaching the throat through the eye, it is not considered a fast-breaking act. If you are not certain that something has invalidated your fast, then your fast is valid and is not nullified by doubt. You are not required to make up the day unless you are certain that an invalidating act occurred, such as water reaching the throat during ghusl. You should disregard obsessive thoughts and not succumb to them.