dedication and all is fine...but our body is not a laboratory for doing such extreme things that is against nature........ as thirumoolar says, udal valarthen, uyir valarthene..... have to respect one's body and mind........ thatz why they call Sivaji as emperor in acting...without doing anything drastic to the body nor with overdose / plastic makeup he went on to create the desired impact a character needed......
http://www.youtube.com/watch?v=_tDQPvWEL5c
in the opening sequences..just some face movements and sivaji makes us feel the pain of the character he is playing..great...