I would caution you against using any "permanent" dermal filler that cannot be easily removed, particularly to treat HIV lipoatrophy. Most of these type of fillers used for this particular problem have resulted in fairly severe complications that may be quite hard, expensive and unsuccessfully treated. Stick to a good volume HA filler and do touch ups every 9 to 12 months and you will likely have a very safe and long term improvement of your facial appearance.
Dr. Barnett is truly "one of the great ones", and his personal experience with microdroplet silicone is unmatched by anyone still practicing. Would highly recommend visiting their practice for more information on microdroplet silicone for facial lipoatrophy, so you could see if this is something that might be right for you.
Hope this helps you.