What happens next?

How to deal with parrotlet aggression
Identify when your parrotlet is most aggressive.
Aggression could be due to a number of causes, so observation is the first step to correcting the behavior. Note if your parrotlet is aggressive when you touch it or in response to specific sights and sounds.
If your pet bites or lunges when you touch it, you might be handling it too roughly. Give it some space, offer treats to make it more comfortable with you, and work on being more gentle when you handle it.