definitely false imprisonment and child endangerment! she was left unsupervised, anything could have happened to her. Did the teacher tell you why she was being punished? Did your daughter say if this happens alot? contact the school board and see if this is standard policy, if it has happened...
You need to go to the doctor as soon as possible, because if you wait it will appear that you are fine but realized that you could sue for personal injury and get some money out of it. You will need the doctor to say that there is something wrong with your back, so get it checked up on...
I doubt you could get anything from just slipping. Its a water park, thats a risk you take by going there. If someone or something had CAUSED you to slip, that would be different. But I doubt anything will come of it..
I think the only way you would get anything from this is if you didnt get the cover, but you did, so you cant see the uneven tooth, correct? So you want to sue for the 2 weeks you had an uneven tooth? Did you sign a contract that expressed the insurance details and coverage, or just took their...
2nd opinion
I would seek a second opinion from another doctor to make sure the injury is not permanent. Although you should get some compensation for the medical bills.