What is the most natural filler ?

You can use fat or hyaluronic acid fillers, both are natural substances in your body.  Best, Dr. Emer.

The most natural looking filler depends on how your facial structure is and what you are trying to accomplish. Hyaluronic fillers and Sculptra are the most natural looking fillers.  

You had scarring from PDL treatment? how? were you burnt? if a scar is depressed and subsequently released with submission as you report, it should be injected immediately with a filler or fat to maintain the space so the scar does not reindent. I take it you did not have the filler treatment before and now the scar has reformed with indentation. In that case, it may require submission again and I would recommend HA filler, any one of the fad approved ones is fine.

When a patient has a history of multiple allergies or of autoimmune disease, I generally recommend using a hyaluronic acid gel filler.  Hyaluronic acid gel fillers are derived from hyaluronic acid from a bacterial source that is very similar to hyaluronic acid found naturally in human skin.  That means it is very unlikely for human skin to react to hyaluronic acid gel fillers as something foreign and they are unlikely to stimulate an allergic reaction.  Another benefit for a patient with your concerns is that hyaluronic acid gel fillers can be dissolved after implantation using hyaluronidase, an enzyme injected directly into the area of filler.It may also be a good idea to have your infectious disease/Lyme physician speak with your dermatologist or surgeon prior to being treated so that all your providers are comfortable with your care.I hope this answer was helpful.Best wishes.