Does it look like the tooth has moved at all?
It looks like what's called a subluxation injury, what that means is knocking the tooth has slightly damaged the attachment holding the tooth in, causing bleeding. No damage to the tooth itself just where the gum attaches to the tooth.
It's nothing to worry about, it's just a slight bruising of the tissues that hold the tooth in really. It will heal absolutely fine.
It would be worth getting her to a dentist to take an x-ray to check there's no damage to the root, I would try and get an appointment within the next week or so.
You may notice the baby tooth starts to discolour, which is normally nothing to worry about.
The only thing to be a aware of is the developing adult tooth underneath, at 4 I would expect the crown to be already formed and if the tooth hasn't moved the chance that any damage has happened is very low. You would potentially get a white spot on her adult tooth or a slight malformation of the roots, but normally this doesn't cause any problems.
I really think there's absolutely nothing to worry about! It looks fine if for a bit of bleeding, you are doing the right things with a soft diet and gentle cleaning!