Removing silicone from the buttocks
I am one of the leading experts in liquid silicone removal. Once the silicone reaction has reached the skin, it is very difficult to remove the material completely.
Silicone injection problem
Injection of silicone to buttocks and breasts is a real problem and often leads to a significant deformity of the body. In your situation, the reason for redness (discoloration) is the reaction to the injected silicone very close to the skin and dermis. Unfortunately, this kind of reaction continues and eventually the area becomes very firm. If there is no skin discoloration, it usually indicates the injection was done deeply, not too close to skin, and thus, removal does not involve removal of the skin over the injection. I would suggest starting from local plastic surgeons who practice in the local hospitals.