after a total rescape of the tank it's very possible that you lost your biological filter, which would cause a high level of ammonia and 0 nitrite and nitrate. abrasions from the fall may be irritated by a high ammonia level when otherwise just a fall or just ammonia wouldn't produce the same irritation. if the tap is bad, a good dechlorinating product like Prime will help to remove most harmful substances like chlorine, ammonia, or chloramines.
