You might be looking at an internal injury that may be skeletal (a broken or fracture bone) - muscular (strain/sprain) or even internal bleed (not likely, but possible).
A fracture or break makes the bird prone to infection which can happen pretty quickly so a hands on examination is essential in order to first diagnose what's wrong and then actually treat it.
There is no at home treatment option until the problem is determined. Let's say your human toddler falls and ends up favoring a leg. Do you decide to treat it yourself or do you get that child to a doctor and likely x-rays to figure out why they favor that leg?
How far is too far; how much is too much (to spend) on your toddler?
That's what we must ask ourselves even when it's a feathered 'toddler'. Your bird has the human mental and emotional development and sentience as a human 3-4 year old.
Another rather harsh, but true factor here is that in some 20- plus years working with birds I've seen only one succumb to being brought in for a hands on exam and it was an elderly macaw with heart disease.
Other than that - I've seen a huge percentage of birds die from not being brought in as compared to those who are (brought in.
When it comes to injuries you can’t see, you must keep reminding yourself that birds, probably more than most other species of animal, have overwhelming instincts that drive them to hide illness, weakness or injury at all cost. They will often eat, drink, behave and even vocalize quite normally until they can’t maintain the act any longer.
--- By the time we see symptoms, it is usually pretty severe, sometimes it’s even too late to fix.
--- This is why I encourage you to trust your own instincts first and foremost. Don’t talk yourself out of a vet or clinic visit and with a bird that has been injured it’s rarely a good idea to wait and see how it goes.
--- Fractures, breaks and other traumas that cannot be seen may become infected at the internal site or heal so badly that the bird ends up paralyzed, arthritic or with other complications that no bird should have to live with. ---
Now it's up to you. Only you know your bird well enough to make a decision based on what you're seeing, your instincts and gut feelings
You got this, right?