Knots may be sutures
Knots that you are feeling in your stomach area after a tummy tuck may be knots from sutures underneath the skin. Usually they dissolve with time.
But if they do not, then you may need to have them surgically removed. Knots can also be caused by internal scar tissue.
In your case, that is a good possibility because you are able to get them smaller by massaging.
Unless the skin opens up over the knots or there is severe pain, they are probably nothing to worry about. (James Tang, MD, Houston Plastic Surgeon)
Internal scar tissues after a tummy tuck
It is not uncommon for patients to feel small bumps or areas of firmness beneath their scar after a tummy tuck.
Most of the time these bumps resolve on their own with massage and patience. I frequently tell my patients that it takes at least a year for their scars to heal completely and take on their permanent appearance. Sometimes, knots from sutures fail to dissolve completely and can become exposed. These exposed portions of suture material can be removed by your surgeon or their staff. (Kelly Gallego, MD, FACS, Yuba City Plastic Surgeon)
Recovery from Tummy Tuck / Abdominoplasty
After surgery, it is not uncommon to feel knots or lumps or bumps which are all temporary. However, it may take several months for the scar tissues to settle and the swelling to resolve.
Occasionally in very thin patients, they can actually feel the knot of the sutures. In most cases, this is prevent by inverting or tying the knot up side down so that it points inward. However, sometimes these are still palpable. It would be best to discuss your concerns with your surgeon and they can be very helpful and understanding your concerns. (David Shafer, MD, New York Plastic Surgeon)
Knots under incision
If you feel knots under your incision it can be due to: A real knot from the sutures used to close your incision. These usually dissolve on their own with time or your surgeon can remove them in the office with some local anesthesia to numb you. Internal scar tissue and swelling which can feel uneven. This is best helped with scar massage which basically involves rubbing the areas with a finger for several minutes a few times per day. These usually go away on their own in a couple months. (Adam Hamawy, MD, Princeton Plastic Surgeon)
Normal after tummy tuck
I would not massage these areas until the wounds are well healed, typically after 2 months. There are scars and sutures which can give you the lumps, neither of which are dangerous. (Gary Lawton, MD, FACS, San Antonio Plastic Surgeon)