What is the ruling on swallowing one or two nose hairs while fasting? And does that necessitate making up the fast or offering expiation?

You are afflicted with waswasah (obsessive whispering); beware of it and do not succumb to it. If hairs entered your throat unintentionally and you swallowed them, your fast is valid—Allah willing—and you are not required to repeat it. This is because one of the conditions for invalidating the fast is intentionality. Allah Almighty says: "And there is no blame upon you for that in which you have erred, but [only for] what your hearts have intended."