Allergies! I am allergic to dairy and just by eating one cookie (which has egg) my throat and tongue get like that. If I have more or add another dairy product I get the swelling and hives!
Swollen neck with swollen tongue can happen due to certain viral infcetions, hypothyroidism, Hashimoto’s disease, hypersensitivity reaction to certain antibiotics especially if not taken before and allergies.
I would recommend that you encourage your daughter to consult a physician for complete evaluation nad confirmation of the cause for this. Best.