My mother had a concussion from a stair fall some years ago, which didn't set in until some time later. She had terrible dizziness/vertigo for days, but no vomiting, and no bleeding from the bump on her head.

So it's possible to have a concussion without vomiting or without a bleeding head bump... and the symptoms of concussion can be delayed by hours.

If you just want her badly rattled, enough to make her stunned/disconnected for a while (but not actually concussed), you could probably do that, too; not all head bumps lead to drastic complications.