Liquid silicone is unsafe, please do not use it ever. The autoimmune response could be triggered by this substance, if you look around on th Internet, you will find patients that have a lot of problems with this product. The use for lips and other areas is off label. The inical use is for retine problems.
Do not use silicone injections. Both silicone 1000 and silicone 5000 are silicones. It does not matter if it is dense or less dense, if it has more weight or less molecular weight, the problem is that the immune system reacts against them and produces inflammations and degeneration of the tissues, then the recommendation is not to inject it. If you search in the Internet you will find positive comments, but also search negative comments from people who had complications with this product. If you want to increase your lips, use hyaluronic acid, for example Juvederm, that is safe and effective.
Please remember to be aware, do not let any permanenrt filler to be injected into your face, breast, buttocks, calfs, genitalia, etc. The safest way to increase buttocks is through your own fat injections or through silicone implants.
I hope the information was usefull, have a nice day! Dr Carlos Alberto Ríos.