Lump after neck lift - is this fat or a possible seroma? 3 years post op (photo)

That looks like bunching of the medial parts of the platysmal muscle bellies; during a platysmaplasty, surgeons will suture the left/right medial muscle bellies of the platysma. If this is done poorly or scars poorly, it can form webbing/scar ball/exaggerated bands. I would recommend a revision necklift with direct excision of that scar ball/platysmal band. I would go see an American Board of Plastic Surgery certified surgery who has experience in facial rejuvenation. This ensures that your surgeon has done proper accredited real plastic surgery training.

Thank you for your inquiry and sharing your photograph. I am sorry that you have experienced problems after your neck lift surgery. The images suggest a combination of a band of scar contracture under the skin and potentially a small amount of fatty tissue. You can use an ultrasound examination to have a clear diagnosis of the problem. This will allow you to discuss with your surgeon whether a revision procedure is suitable.

I encourage you to return to your surgeon for an evaluation. Since the lump has been there since the time of your surgery three years ago it is unlikely to resolve without intervention. If your surgeon can't determine the nature of the lump with a physical exam further testing such as an ultrasound may be helpful.