Are you saying you entered the family name as your first name and vice versa? I'm sorry, but there is not much you can do at this point since most likely you would be disqualified at the time of the interview even if you were to get selected. Registering again with the correct info would get you disqualified for sure for duplicate entries.
If you are serious about your participation at the lottery, you should take your time to verify all the data you entered before submitting the form, especially since there is also a summary page where you can review the information once again before completing the registration.