How do I enter a completed course on FLVS (Florida Virtual School)?

Unfortunately, no. Once you have completed a course, there isn't another way to get inside. You would have to request the course once again, and that would only work if you failed the course. But no, there isn't any way.

Well I'm not sure about FLVS, because that's not what I'm doing. But if you want to graduate early, you can do what I'm doing. As of January I was a sophmore in High School, my school sucked so I started looking for homeschool options. I started doing what my mom did for home schooling. It's called American School of Correspondence. Obviously you have to pay, but in total you only need 18 credits to graduate (music and pe don't count as credits they accept), but they send you the books, you do the small bit of reading and send them back the open-book exams after the lessons you read. If you do 2 exams a day, or work for like 4 hours, 4 days a week (through the summer/or even take breaks for summer and graduate by March/April next year), you should be able to graduate in a year. Like me, I should be graduated by October at the earliest and December at the latest and I don't do much everyday, I sleep in, and work on work from 10am-noonish. Just a though you might want to consider, unless you want to spend Senior year in public school, going to prom, and walking with your class and everything.