Neymar, 26, endured widespread criticism from media for his play-acting and lack of leadership during Russia 2018.
With Brazil falling at the quarter-final stage to Belgium 2-1, the world-record transfer holder also made headlines for refusing to attend the post-match press conference.
However, he's opened up about the ordeal that has somewhat tarnished his image as a global icon.
"You may think I exaggerate. And sometimes I do exaggerate. But the truth is I suffer on the pitch," Neymar said in the advert sponsored by Gillette.
"When I leave without giving interviews, it is not because I only want the victory laurels - it is because I still haven't learned to disappoint you.
"When I look impolite, it is not because I am a spoiled kid. It is because I have not learned how to be frustrated.
"I took long to accept your criticism. I took long to look at myself in the mirror and become a new man,