Your child cannot become addicted to tylenol - it is not a habit forming medication, or it would not be approved for use in infants and children. As long as you are giving only the dose recommended by the doctor and/or the dosage instructions on the bottle, there is no harm in giving him a dose before bed for awhile until the worst of the teething is over. Generally, the teething pain calms down significantly once the tooth actually breaks through the surface of the gums. With teething, all you can really do is try out different methods of comfort as you have already and give tylenol as needed when he is really upset - if a single dose of tylenol every night until his teeth come through is what helps him and allows him to sleep, then by all means, comfort your childs pain! It wont go on forever, and we are lucky we as parents are able to relieve our infant's teething so easily - have you tried infant orajel? It relieves teething pain topically.