PDO Threads are considered a "new phenomenon". This can put some people off, but they have been in use internationally for over a decade. They are FDA approved and almost entirely non-invasive.
Side effects are minimal and rare, as with most procedures based on natural process; however, slight swelling and tenderness after injection are possible. More severe cases are extremely uncommon, although protruding thread, infection, and asymmetry have been reported in the past.