My daughter's lip swells massively when she bites it

[Miran12]

My daughter is 9 & almost every time she bites her lip, no breaking of the skin, her lip swells up like a balloon. Drs tried to say it was an allergy & gave her adrenaline and anti histamine which does nothing. The only thing that works is ibruprofen but surely this is not normal? It happens quite a lot & swells up so big it looks like it's going to burst.

A lip trauma can very painful and dramatic looking. If antihistamines are making no difference but ibuprofen is then I'd be inclined to think it was inflammation due to the biting and not an allergy. Could she be encouraged not to bite her lip?