I'd rather wait and ask my buddy during study hall. Hygiene is particularly important for smokers or coffee drinkers. Keep mints, Binaca, even mouth wash in your desk drawer. If possible, bring a toothbrush and toothpaste and make sure you use them after lunch period or smoke breaks. Use deodorant and check its effectiveness periodically.
Some students are even allergic to perfumes.
Also, check your teeth periodically to see if lipstick has rubbed off on them. It's a good idea to avoid applying make-up or doing your hair in the presence of others.