back of the neck could be (no joke) that they had pain there there is something to put the havdolah wine on parts of the body that hurt or need a refuah in anyway! there is also a sugulah to put on the mouth of a child who doesnt speak yet (delayed) and u say st dont remember what
supposly alot of koach the hadolah wine
some even springle it by the door to their house 3x