Assess your strength of character. Those with strong character will listen to the feedback. Think with resolve and leaving emotion out of it, often agree with portion of it. Next, a strong character will incorporate feedback into their work and produce an improved work product. Guard against excessive emotion. Attaching your self-worth to the feedback creates disconnect and havoc in the mind and that will result in even more chaotic work product. A strong character listens, incorporates and acts with others in mind.
Be honest. If the boss has some accurate points, own them. Listen to how you can improve and do it! There is nothing wrong with the ultimate result here.