I am not aware of cases of Botox wearing off quickly when there was a much quicker onset of action. The few patients I have in whom Botox wears off in between 4 and 8 weeks do not see it starting to work before all the other patients whose Botox treatments lasts 3 to 4 months.
Our bodies do heal on their own time table. Within one to two weeks you should improve from a contact dermatitis. Follow up with your treating physician if you don't see any change in a week. You may also inquire about a Medrol Dosepak.