Must I repeat fasting the entire month of Ramadan because I swallowed my saliva along with parts of my lips, knowing that I was ignorant of the ruling on that at the time of fasting?

If a fasting person bites the skin of their lips, they must remove it. If they swallow it forgetfully, or do not find any trace of it, or find it difficult to remove and swallow it with their saliva, their fast is valid. However, if they intentionally swallow it despite being able to remove it, their fast is invalidated. So, if you swallowed the skin of your lips when you were able to spit it out, your fast is not valid, and you must make up the days on which you did that.