Americans put Band-Aids on their boo boos. Brits use Elastoplasts. Two fine examples of a brand name that has become so ubiquitous it has replaced the actual word.
Late Note: From the wealth of comments, apparently I've got this all wrong as a commonly used term. It's really called 'sticking plaster', which is way funnier.
Also, my word, you guys don't say boo boo? Boo boo: minor injury, especially referring to children. It's just cute to say, especially in your most annoying baby voicy. "Does him have a widdle boo boo? Aw, I so sorry!"
We have two Boo Boo Bunnies that reside in the freezer. They are washcloth bunny rabbits with ice cores, which when applied to a boo boo give miraculous healing powers. At least that is what my youngest says.