Lets say you go to production site GIT and fire "git pull" command, something goes wrong, there are conflicts and you start to panic. Proper solution for this is to write
git reset --hard
This will clean the mess and put GIT to state before this.
Also if you want to be double sure, make a branch out of current MASTER, like Master-tmp and you can quickly switch to that one, if things go wrong.
git checkout master-tmp