Thank you for your query.
There is no reason to panic.
This is a normal phenonmenon after injury
to the buccal mucous membrane
.It will subside in a few days.Avoid licking the areas as it will delay the recovery.If there is any cut apply some local antibiotic
or gel.Application of an ice pack locally should help too.Hope it answers your query.Wishing your child a speedy recovery.Bye