The Endotine device is not a Forehead (Brow) lift technique but a way to hold the elevated forehead in place until mature scar forms and holds it there. The endotine has two surfaces; one that has a small peg which pits inside the outer table of bone of the skull (holding it in place) and a multi-spine surface which engages the underside of the forehead deep (galea) layer holding it suspended in place. In addition to the potential complications associated with the specific Forehead Lift utilized the endotines are palpable for up to 5-6 months (until it dissolves) and may even be visible as two bumps (Not quite a "Hellboy" appearance). The endotines may cause local inflammation, may become infected and in very rare cases in very thin skin individuals may puncture through the skin. What you must know is that there is no ONE ideal way to fold the forehead in place. The fact that there are still so many ways to do it, instead of a one asccepted norm, should tell you that there is no ideal way and surgeons use the method which served them best.
The complications depend on the approach that is used but are generally similar to a normal brow lift. However, some patients with thin skin have found the Endotine to be palpable (easy to feel) under the skin, until the product dissolves.