Tiny Cut/bruise on Chin

Any bruise is a hematoma so I'm not sure why you call it a "hematoma bruise" - is there a specific distinction you're trying to make?

If there's some blood that has to be absorbed by the body, it may take little while longer. There could also be a small amount of scar tissue that just has to break down over time. I think it would be better if you left it alone lest you keep irritating it. These things usually resolve themselves. Try not to be impatient. You can mention it to the doctor next time you're there, but I wouldn't make a special trip if there is clearly no redness or infection from a tiny cut. I don't know how old your daughter is, but I think you can reasonably expect a lot of these injuries over the years!

I walked into an end table and have a pretty ugly and obvious bruise on my leg. There is a lump there and I imagine that is just what happens when the blood is trapped under the skin. It will all go away soon. I did this prior to Sunday and don't imagine the bruise or lump will go away in the next few days.

Give it a few more days.

Happens to my shins all the time... The bump goes away, but it takes longer to go than the bruise does.

If you stop poking at it the bump will go away faster.

I had this happen when I hit my forearm into the side of our sliding glass door( my pup ran out into the yard, but I still had the leash in my hand) it bruised, but a bump formed. Sometimes a scrape/bruise that bangs into bone will break off tiny fragments of bone, and it will form a bump. It does go away on its own, and is usually nothing to worry about. I iced mine occasionally and applied heat as well.

I took a dog bite to my leg which broke the skin and bruised pretty badly. I think it took about 3 months for the lumps under the skin to go away.

I'd guess your daughter's will go away a lot quicker since her injury was mild.