Little borther has a huge white swollen bump on his lip after eating from coming home from dentist. either anesthesia or infection from biting lip?

Lip bump: It's most likely trauma from a bite under Lidocaine anesthsia.

Very common: Bitten or chewed lip after dental treatment is a common complication. After the dental anesthesia the area and the lip will be numb for an additional 2 hours or so. If the child does manage to bite their lips, cheek, or tongue, the area may become swollen, and a large wound may develop. This scary wound will take 7-10 days to heal. Rec.: call your dentist for future recommendations.

No: his lip is probably still numb and he bit it causing it to swell

Bit lip???: Possible that you bit your lip. Hard to say without seeing, but most likely cause

Bit LIp: It sounds like the things you see when a patient bites the lip after having local anesthesia. These things usually go away in a couple of days.