One of the worst mistakes I made was 'finishing out the year'. It didn't do irreparable damage to my son, but it took 2 years to rectify, and 6 months before we could even begin to see the light at the end of the tunnel.
I should have pulled him at winter break. Instead, I let him be miserable and learn to hate & fear school of ANY kind (when school had been his favorite thing for 3 years, prior). He was an absolute mess by June.
So, from my experience, Id yank her, deschool for a couple months if necessary (may be, maybe not, since you're returning... Not starting... And its only been 6mo, her brain may not have turned off, yet), and then start back up.
I kept him in for the silly idea of missing his friends.
He saw his friends a lot more AFTER starting homeschool... Because of the time and the fact that he was energetic & happy again. AFTER 6 months of some really painful transition. My son was a MESS.
Do keep in mind deschooling. It may or may not be necessary... But k12 awayschool students are told what to do minute by minute. Its hard enough for them to adjust to summer break & not being told what to do all the time... Switching back to HS'ing, where one is an active participant and needs to be thinking/planning/participating ... Will either be a huge relief or "What did they DO to you??? Where's my little girl???" They didn't do anything/she'll be fine and be back to herself in a few weeks. Its just easy to forget the paradigm switch that happens.