The school owes each of its students (and parents) a 'duty of care' to do what ever is reasonable in respect of the students welfare and safety. If they have been negligent (or breached their duty of care) then you may have a case for compensation. This can only be established by a specialist injury lawyer who can review the facts of what happened. You should also consider the extent of any compensation if negligence can be proved. The time and trouble to recover medical expenses may not be worthwhile.