I didn't see exactly what happened yesterday, but when I looked over, Alec was on his knees in front of the wooden castle, starting that slow cry that lets you know they're building up to a good howl because they're really hurt. It quickly became clear his mouth was bleeding, and the little inspection I was allowed to do showed all of his teeth and what looked like some scraped skin on the inside of his upper lip, so I applied pressure and cuddles and thanked my lucky stars it wasn't worse.
Well, until I noticed he kept rubbing his lower teeth against his upper teeth and that when he did, one of his front teeth was at a distinctly different angle than the other. Oh crud. A quick Googling revealed that a baby tooth knocked loose wasn't a dental emergency worthy of a visit to the dentist on a Saturday night (because of course this sort of things always happens at 4:30 on a Saturday). So I cuddled him some more and tried to control my inner freakout, because dental injuries squick me right out. It's here that his infant habit of sucking our fingers for comfort came in handy (we're trying to wean him off of it, but it's a process, and oh, don't even start), because my finger in his mouth held his loose tooth in place for what turned out to be over an hour because he fell asleep and I didn't want to pull my finger out for fear of yanking it out of place.
I'm not sure how much you can do for a two-year-old with a loose tooth. Soft foods, try to stay alert to keep him from messing with it and a call to the dentist tomorrow. Apparently it will hopefully reattach itself with time. We just have to keep him from knocking it out of his fool head in the meantime, since he certainly doesn't see why he shouldn't try to practice all of his wrestling moves on his sister or use the couch for gymnastics practice. Oy.