I happened to catch a short clip on TV long time ago about Chinese "ear massage" that supposedly help one to reduce feeling of stress. I sometimes apply these techniques when I feel the built up of stress and it somewhat calms me a bit. Since your child can't carry out the other techniques mentioned below in exam hall, just do the ears - rubbing and massaging her ears before exam to relax herself...But ask her to practice first at home to see whether it works for her.

Extract from internet: (Editor's note: Need citation)

Chinese self-massage techniques can help relax your body, release tension and reduce anxiety - all this and more without spending a single penny.