I've been taking penicillin for a tooth infection. Three hours ago I took my last dosage. All together I took it for 9 1/2 days, 4 times a day every six hours. Originally I had an appointment for tomorrow to get a root canal, but my parents had to cancel because they are leaving tomorrow morning for a cruise. Now my appointment is on the 20th. How likely is it that the infection will come back before then? I am very worried about this.