Exams and presentations are the worst with PATM, especially because my school has lectures with upwards of 300 students. A quick and easy thing to do is to cleanse your face right before the presentation; wash in hot water and the really cold water. You could fast, I've found that digesting large amounts food worsens PATM, but this might hurt your performance. The unreasonably loud coughers are the worst part, but you just have to talk louder. Good luck!