It initially seemed the attempt to kill Heydrich had failed. But he died in Prague's Bulovka hospital eight days later, reportedly from septicaemia from the shrapnel, or possibly fragments of upholstery.
It's of little consolation to his victims' families that Heydrich died in the most excruciating pain imaginable from the needle-like horsehairs from his Mercedes' upholstery being driven into his body by the force of the explosion, most of which couldn't be removed by surgery...His every movement was a new adventure in pain...He probably eventually welcomed the death caused by septicemia brought on by the micro-organisms in the horsehair......Ben

Edit: A good book on the subject is "Hitler's Hangman" by Robert Gerwarth...