When you first get your braces on, your teeth will hurt for a few days, as they will every time you get your braces tightened or your wires changed.
Chamomile is also popular for anxiety in children. Fennel. Fennel isn't for anxiety specifically, but it is linked to treating some of the most common symptoms of anxiety, including digestion, coughing (many with anxiety have a nervous cough), and asthma (anxiety can exacerbate asthma symptoms).
Antihistamines (such as hydroxyzine) and beta-blockers (such as propranolol) can help mild cases of anxiety as well as performance anxiety, a type of social anxiety disorder. Antidepressants such as SSRIs or SNRIs or tricyclics need to be taken daily whether or not you have anxiety on that particular day, as prescribed by your health care provider.