Generally speaking fat embolus occurs at the time of procedure when a vessel is inadvertently cannulated and fat injected into the intravascular space. However, the symptoms (respiratory distress, neurologic changes and petechial rash) may not manifest immediately.This is a known complication of the procedure but can be avoided by avoidance of the submuscular plane, aspiration before injection and the use of large bore blunt cannulas. Once an embolus occurs, treatment is supportive but early diagnosis is crucial for good outcomes.As always, discuss your concerns with a board certified plastic surgeon (ABPS).
It is possible to get an embolism during recovery depending upon the techniques used. Fat injection through large bore blunt cannula above the muscle makes it virtually impossible to get a fat embolus, but the risk for fat necrosis and infection is likely higher due to reduced vascularity of that area.