Brief Answer:
could be allergic

Detailed Answer:
Hello,

lip swelling could be an allergic reaction. If she hasn't eaten it in the past then perhaps she's allergic to it and she's just found out. If all the symptoms are confined to lip swelling then it's not a dangerous situation. If the swelling is spread elsewhere like the airways then it could become a very dangerous situation. You'd better visit your doctor at once for clinical assessment and appropriate treatment. Such conditions are usually treated with antihistamines.

Kind Regards!

---

Brief Answer:
Most likely an allergic reaction from the contents.

Detailed Answer:
Hi

Thank you for asking HCM

I have gone through your query. Your daughter's problem can be most likely allergic reaction from any of the contents of crackers. If she is not getting swelling of respiratory passage then nothing to worry. If she is feeling swelling in throat or respiratory discomfort or dizziness then you should approach ER. In such case corticosteroid injection will be needed.
For now you ca give her antihistamines like benadryl or cetirizine (zyrtec). These are available over the counter. If zyrtec then once daily for adult. Benadryl for adult can give twice or thrice daily. You can also apply hydocortisone cream on swollen lip. Avoid aspirin in this case.
Let me know if anything not clear.I am happy to help you.
Thanks.

---