"Ele não se expressou bem."

Translation: He did not express himself well.

[scraff]

Can this also be "Ele não expressou-se bem"?

[Paulenrique]

No. In Portuguese, we say "Não" is an "attractive" word, it means the pronouns shoul surround it. Therefore, "se" has to be after "não".

[DREDWARD]

What about Doesn't, we don't know the context??

[Paulenrique]

= ele não se expressa bem.