Can we file a lawsuit for misdiagnosis?

If you can show negligence you should have a chance at recovery.

Yes, but you need an attorney to obtain an expert's evaluation and written opinion. Also, issue of damages and permanency may be an issue

If you can find a doctor who will say that there were signs that a blood test was required, and that failing to take one was malpractice, then you can sue. But, you will also have the burden of proving that by starting therapy at that time, the Bell's palsy would have been prevented, or significantly altered.

In order to prove a medical malpractice case, a claimant must prove a failure to conform to accepted practice, resulting in an injury. A bad result is not enough, and if it is a "judgment call" by the doctor, there is no malpractice, even if the doctor made the wrong call. In your daughter's situation, pain and redness often do indicate infection. There may also be a question as to whether an earlier, correct diagnosis would make a difference in the ultimate treatment and recovery of the Bell's Palsy. Still, an expert opinion might yield a result that the doctor did not use proper protocols and that had he done so, the correct diagnosis would have been made and correct treatment would have been effective. You would need expert opinion testimony in any event, which will cost thousands of dollars. Do not hesitate to contact a lawyer in your area who handles medical malpractice cases.

Not likely. If they followed standard procedures that a reasonable doctor would follow given the symptoms then they will not likely be found negligent.

If the misdiagnosis resulted in further injury that could have been prevented, and if an expert witness who is a doctor practicing in the same field as the treating physician states in an affidavit that the treating physician breached the standard of care in the community, then yes.

Not likely, the Bell's palsy is not a damage caused of the alleged error.

You have to show that that misdiagnosis caused some damage e.g., the Bell's Palsy would not have developed or been as severe if it had been determined the day before. I doubt you could show that; you should consult with some medical malpractice attorneys to see if they feel you have a cause of action.