What are possible side effects of Silikon 1000 in the lips?

Silicone injections are theoretically inert but can exhibit severe complications in a subset of patients. I have personally treated numerous patients with silicone injection complications. In patients with silicone injections, there is a potential for silicone induced deformity deriving from an inflammatory effect against the silicone and/or the silicone itself. This can lead to severe functional and static deformity of the involved area.
We receive countless consultations for silicone injection complications from patients who have gone to Mexico or Tijuana for their injections. After a thorough evaluation, I provide patients with a comprehensive protocol to improve symptoms and reduce the complication profile.

Silikon 1000 is a purified form of silicone that was originally designed for use in retinal surgery behind the eye.  It tends to be non-reactive and granuloma formation (inflammatory nodules) should be rare.  If used as a facial filler, it is most effectively administered using a microdroplet technique that is well described in the medical literature.  Lumps and bumps can often be related to overcorrection or injections not done with a microdroplet technique.  The goal should be undercorrection initially, and with several visits, additional filler is sequentially added to acheive the desired result.  It should be performed by an experienced injector because it is truly a permanent filler.  Many patients are extremely happy after Silikon 1000 augmentation, but it does have risks and is an off-label use.

The vast majority of complications with Silikon 1000 can be minimized using meticulous injection techniques but complciations include but are not limited to infection, migration, cyst formation, loculation, granuloma formation, biofilm formation, nodularity, fibrosis, inflammatory reaction. pain, extrusion/exposure, ulceration,  palpability, visibility, Tyndall effect, intravascular injection with necrosis or embolization,  etc

Silikon-1000 is a permanent filler, so your results, good or bad, are permanent. You must find a board-certified dermatologist or facial plastic surgeon experienced with the micro-droplet technique. You should also have a discussion with your doctor about the FDA's position with respect to using Silikon-1000 in an off-label fashion to enhance your lips. Lastly, you should see many before and after photos demonstrating beautiful results before you pick your doctor and proceed.
In my hands, complications with Silikon-1000 are infrequent. Around 3% of patients will develop a nodule or bump at the site of injection. These typically respond well to dilute triamcinolone injections; rarely they need to be excised. Also, several treatments may be necessary to obtain a desired result.
I've attached a link to my Lip Enhancement photos for your perusal.
I hope this is helpful for you.

In the right hands, liquid injectable silicone (Silikon-1000) is the ideal filler for lip augmentation as it is very precise and gives the most natural-looking results. It is of course permanent, and therefore, you should only consider being treated by a board-certified dermatologist or facial plastic surgeon with experience and expertise in the use of liquid injectable silicone. That being said, as with any filler treatment, side effects include bruising and swelling, which typically resolve within 5-7 days. Very rarely, and not yet in my hands, one can develop a small nodule or bump at the site of injection. However, this is usually related to the injection technique, meaning the silicone was injected too superficially or too much was put in with the injections.