Disavowing a question will deduct the +1 Xper point earned from asking the question as well as the +2 points earned for giving MHO (if you have awarded MHO to both genders before disavowing). You also cannot reclaim the question after it has been Disavowed.
Not necessarily. Rather than sacrificing Xper points, users may instead elect to donate their nasal passages to medical science. The difficult part is, you'll be required to remove them yourself using a grapefruit spoon.