How do you use in english " hacerse " ...example: hacerse el tonto, hacerse daño...?

Question

Answer

You have to add "onerself" to the verb:
"hacerse el tonto" = to make a fool of oneself
"hacerse daño" = to hurt oneself 
This oneself then changes according to the person, for instance I would say "I made a fool of myself" (when talking about me) but "you made a fool of yourself", "he made a fool of himself", "she made a fool of herself".

Answer

yes, indeed, that's the answer :-p