This is one of the more serious and common risks to breast augmentation - or any surgery for that matter. But the hardening and contraction of the scar tissue around a breast implant can cause discomfort and visual deformations. This can be addressed through revision surgery, but can be a troubling side effect.
Infection is a rare complication following breast augmentation but may develop early or late, possibly months or years after the surgery. When it does occur, the implant may have to be removed, at least temporarily. Infection may also weaken the skin and cause protrusion of an implant.
Whatever the implant is made of, it will comprise a shell around a gel or fluid. It is possible for the outer shell to wrinkle, particularly if it contains saline or some other fluid, and this may be obvious if the breast tissue is thin. If required, a wrinkled implant can be removed and replaced by one of a different type. This problem is unlikely to occur with the more solid implant fillings such as "cohesive gel"
While this may not sound like a problem, if you have breast surgery, the incision is usually underneath the breast. When you have excessive swelling, or a seroma formation, this adds extra weight onto that incision, as well as a lot of pressure on the stitches, since they are now trying to hold in twice as much as they were intended to. The fluid will eventually take the path of least resistance, and pop the stitches. Then you have a big wet mess and need to go back into the OR to get re-sewn up. You also have an increased risk of infection until it’s closed up again. In some cases they will put a drain in to prevent it from happening again. Drains are a PITA.
Ruptured or Deflated Implants
Since saline and silicone implants are not comprised purely of Kevlar (hey, new business idea) and are susceptible to wear and tear, implant replacement is always a concern when considering implants for the long run. Although they are surprisingly durable, but they are not impervious to everything nonetheless.
Change in Nipple Sensation
Although any change in nipple sensation after breast augmentation is unlikely to be permanent, the larger the implant the greater the risk. Nipple sensation can occasionally be increased rather than decreased.