Final answer:
Frequent swallowing may indicate bleeding after a tonsillectomy.
Step-by-step explanation:
The finding that may indicate that the child is bleeding following a tonsillectomy is frequent swallowing. When a child is experiencing bleeding after a tonsillectomy, they may swallow more frequently as they try to clear the blood from their throat. This can be a sign of active bleeding and should be reported to a healthcare professional immediately.