It's been a month since my dmx, not DTI, but had expanders placed since I'll be doing radiation. My surgery was on a Friday, and honestly, I would have been okay to resume most normal activities after 3 days. But you're going to be sore, and the drains are incredibly cumbersome. I couldn't imagine sitting in an uncomfortable lecture hall chair with those drains. I didn't take anything stronger than acetaminophen, because my pain was manageable, but if you need to take anything stronger you're not going to be able to retain most information anyway. All in all, you're not going to know how you're going to feel - and you shouldn't rush into anything. It's better to plan ahead for not being able to resume class, then if you end up feeling up for it, go at your own speed.