The most common issue with the Endotine implants is that they can be tender for the first few months after surgery. Most of my patients tell me this resolves in about 2 months, and they quickly learn how to avoid aggravating the area. The other issue is that they can sometimes be noticed as an unusual bumpiness under the skin if they are palced anterior to the hairline. Again, this goes away after a few months. Much less commonly, the implant can slip causing a need to re-do the surgery. Similarly, the brow itself can losen away from the implant. Both situations would allow the brow to fall post-operatively. While some relaxation of the brow position will happen after surgery, a true drop from implant slippage does not happen very often.
The discomfort from Endotines can often be avoided by placing them above horizontal incisions where there will be numbness that can last 6 months. This is long enough time for these devices to disintegrate.