My child is keeping her first fasts. She is exerting a lot. I have read that mucus(snot) from nose going down the throat does not invalidate the fast. Without sounding embarrassing, she tells me that since she has been sniffling she licked some of the snot/mucus that flowed from her nose onto her lips. Does the same ruling applies to her. Is her fast broken?
In principle, if one has some mucus in the nose which is sniffed and it goes to the back of the mouth and into the throat, then such sniffing of the mucus will not break the fast.
However, if the same mucus exits the body, and is then swallowed afterwards, then this will invalidate the fast, and one Qadha’ will be wajib.