It will only edit your team section of the game, but backup your save just to be sure. You can continue to play as normal.
I suggest using basehaxx/browser hax to install menuhax if you want permanent homebrew access if you're on 11.0 though.
being drunk in school was either because drunk on playing field or could not be arsed with one particular Thursday afternoon so went and had some beers and played some games instead before returning for an ill advised last lesson/period