Since she usually both creates and notices these legitimate and fictional boo-boos when we're in and out of the house, and all require a prompt response, I've learned to be prepared. I have boo-boo treatment ready to go wherever we are. Little first aid kit in my purse. Big first aid at home, on both floors. And best first aid kit in my trunk, stocked with anything and everything someone could possibly require when we aren't home.
OK, not really. But I have all the possible remedies that we could potentially need, short of a tourniquet or limb splint.
Recently I put together a specific kit for exactly what we need, and when we use something, I text myself a note to replace it ASAP.
I customized our kit for the typical four year old to six year old injuries and ailments, but there are some really great premade kits that work well too. In fact, that princess kit is currently living in one of my many tote bags, just waiting for scrapes.
I might be accused of being overprepared, but at least we're never caught off guard. And anything that can diminish the anguish of a sobbing preschooler with a scrape is well worth it to me!