Cyst after 1.5 years tummy tuck. (Photos)

Thank you for sharing your question and photographs and I am sorry to hear of your difficulties.  A cyst can develop whether due to a retained stitch or skin that became imbedded and may not grow in size large enough to be noticed for quite some time.  This can be treated with a small in-office procedure and allow for an improved cosmetic result.  Hope this helps.

Suture erosion can happen any time you have a surgical procedure. This is what appears to be the case per your photo. Without an exam it is not possible to determine if this is truly a stitch or some other abscess. Either way, you should at a very minimum see your pcp for exploration and drainage. It would be better to see the surgeon who did your procedure. Depending on your health status you may or may not require and antibiotic for a short time. While it is relatively uncommon to see this as far out as you are it is not unheard of. Leaving this to fester could cause more problems down the road so get it handled sooner rather than later.