Need advice

Can U lose your license over one med error. Does state report u to the BON or is it your employer. Can u sue the employer if he fires u for one med error and not anyone else.
Usually I would say "no" but I guess it all rests upon what type of "med error"
pt recieved his prn pain med in 4 and a half hours rather than in 6 hours . I may have looked at the wrong mar. I have been there a year and this is the first time I have had an error.