How Long Does It Take to Form Collagen Around Silicone Injected into Lips?

This is a controversial subject, as you can see from the answers you received thus far.  Not all Silicone is created equally.  I have used Silikon 1000 for years now and I have NEVER seen a complication stemming from its use in my hands.  I personally am a fan of it and think it is a wonderful option for permanent lip augmentation.  Yes, it is not FDA approved as a filler but saying that it should not be used as such for this reason is rather ridiculous and I am both surprised and disappointed by the responses you received that assert this.  Botox is only approved for cosmetic use for the lines between the brows but all cosmetic surgeons use it to treat wrinkles in other locations where it is not FDA approved for use. If I am not mistaken,  I believe that Juvederm is approved for treatment of the nasolabial folds but all of us use it in many other locations of the body where it is not FDA approved for use.  I believe that more and more surgeons, despite the negative feedback you received and the surrounding controversy are finding that Silikon 1000 is a wonderful filler.   And the anser to your question is 1-2 months.

Free silicone should not be injected as a permanent filler. It is Not FDA approved . Plus the fact that collagen does not form around free silicone. The body reaction to free silicone is the formation of chronic inflamation called granulomas, which can case lumpiness, chronic inflamation and deformity.

 That's not the right question to ask about silicone injections into the lips, IMHO.  Ask about the complications including silicone moving, creating benign silicone based tumors and most common IMO are the over-sized swollen, disfigured lips it can and does create.  If you're looking for permanent lip augmentation, consider Alloderm or solid silastic Lip Implants.  Do a quick Google search on complications from silicone lip injections before proceeding.