1. One who completely forgot to count and counted neither that night nor during the following daytime hours, does continue to count on the remaining days. This is because according to manyposkimthe counting of each day is a separate mitzvah not dependant on the other days. However, he no longer counts with the blessing because there areposkimwho maintain that all the days are dependant on each other, and according to them reciting the blessing would be a blessing in vain. In this situation it is proper to listen to another person recite the blessing (Shulchan Aruch and Mishnah Berurah 489.).
2. If one realizes today that he erred in his counting yesterday i.e., he counted the wrong number], his status is the same as one who did not count at all, and he continues to count the remaining days without reciting the blessing (ibid.).

