My advice is to wait a little longer. The uneven aspect of the nostrils may be a consequence of a number of things related to the surgery not solely the implant. A third surgery on the nose is definitely no simple matter. Options for donor sources include ear and rib. Ear cartilage as an onlay graft works ok but it is not a great structural graft and this cartilage can have some irregularities which can show through over time. Wrapping cartilage in dermis or overlaying dermis will look good at first, but can decrease the viability of the cartilage and contribute to resorption because cartilage nourishment is coming from contact with the skins blood supply.
When more graft material is necessary, I prefer using ones own rib cartilage taken from underneath the rectus muscle so that it does not create a deformity. Warping can be an issue so one has to work very hard at fashioning the graft from a piece that does not exhibit this tendency. I have not used cadaver cartilage for this purpose. I have also had success with medpore, which is a porous although more rigid onlay graft which appears to be more resistant to infection. This graft I do cover with acellular dermis to avoid adhesion to the skin which can create some outlining of the graft.
First. Wait one year. Do NOT use Goretex or rib. If you need revision see a very experienced revision rhinoplasty surgeon. In 35 years I have never use synthetic materials in noses. Far will absorb unreliably. Your septal or ear cartilage should be used. I have never had an infection with these.
You need to wait for at least a year before a revision rhinoplasty. From the limited photos; I believe a rib graft would be the best way to proceed in your case. Find a board certified surgeon who is well versed in rhinoplasty. Donald R Nunn MD Atlanta Plastic Surgeon
Still to soon for any more surgery. Allow 6 months of healing before attempting allograft or autografts.////
Rib cartilage is often the best to give a moderate dorsal projection because often the septum does not provide enough. I have used irradiated cartilage ( cadaver donor) with success.