Lovato, 18, was freed in time to go home for the Christmas weekend. Officials will determine whether she needs to go back, a source said.
She was sent to Rehab for reportedly punching dancer Alex Welch in the face on a private jet in October.
Welch, whose face was bruised, subsequently received an undisclosed monetary settlement, according to reports.
Lovato's spokesman has described the rehab stay as needed for 'emotional and physical issues' - but declined to confirm reports that Lovato may have tried to hurt herself.