Tummy tuck incision looks to be opening and draining 3 weeks post op. Is this normal? (Photo)

The incision itself does not look to be too much of a problem.  Although this is not normal it could just be spitting stitches.  The drainage however is a major issue.  Having an opening in the wound and drainage is a set up for infection.  You need to be treated by a local plastic surgeon, which may be difficult to find. You are likely to need more than just oral antibiotics.

I am sorry to hear about the complication you are experiencing. Superficial separation of the incision line is a known complication after tummy tuck surgery. Close follow up with your plastic surgeon will be in your best interests; sometimes removal of a exposed suture and/or removal of any unhealthy tissue will expedite healing. Otherwise, wound care regimens will differ from one plastic surgeon to another. Generally, this will involve application of some type of sterile dressing ( in my practice I use a non-stick dressing covered by a sterile dressing). You should have peace of mind that these types of wound healing problems generally go on to heal over the course of the next several weeks, without long-term sequelae. Also important to concentrate on a healthy diet, including good protein source. Occasionally, in the event of a wider scar, scar revision surgery may be helpful down the line. Best wishes.

Thanks for your question and pic.  I recommend establishing care with a local board certified  plastic surgeon for evaluation.  You may have some "spitting sutures" that may have to be removed in the near future. Best of luck.