My 2.5 yr old son 試過跌親門牙 and I also 發覺佢隻門牙鬆鬆地 afterward! I took him to see dentist and the dentist said that what we could do is to continue observing. If his tooth turns in gray/dark colour later, then the tooth is dead, need to remove it. Then we waited and waited..... about 2 months later, his tooth is ok now. 自己"實"返 la. I think you can wait and observe for some days. If in doubt, consult with the dentist.
You check check if the tooth is painful during eating, and if there is any bleeding over the gum. The best thing to do is to see a dentist. If there is infection, may need to take some medication or have treatment to the tooth. Otherwise, if the infection is untreated, it may affect the "adult tooth" gar!
No need to worry too much. My dentist said 隻牙會自己"實"返 soon. Of course, you should consult the dentist if you find your daughter always eats by pass that tooth, feels painful when using that tooth, or that tooth looks strange later.
My son was 甩左隻門牙 (全隻,上面右邊) in an accident on 3Dec. He'll be 2yrs old on coming Sun. The dentist said there's nothing can be done but just wait 換恆齒. 上面右邊門牙 was also 鬆鬆地 but it's firmed few days later.
Btw, my colleague's daughter was same as your daughter few years ago. She's 換恆齒 now and so far ok.