I am not sure how it effects skin.....I am sure using it differently will work differently but basically almost everyone on the corn site I visit has been using it for quite a long time now....at least a year. No side effects so far.
It REALLY cleaned up mouse colonies...man less crap, better overall health. and big time for the snakes too but you really notice it when you start using it in mice colonies.
I also give this to our cats (who sometimes get outside and kill things and eat them) and my dog to help treat for any parasites it works on, or anything. Its great that it is both natural, a anti-biotic AND anti-parasitic.