Hello, my name isXXXXX and I have over 20 years of experience as a veterinarian.
Congratulations on getting Alin through gastric dilatation and torsion surgery. That can be a very difficult surgery itself and recovery is never a smooth process, we often have complications because of the scope of the surgery, poor blood flow to the incisions due to heart arrhythmias and blood clots because of the primary disease process. Secondary incision infections are common.
When we see an infection we can almost always assume that there won't be normal healing and we will see more scar tissue forming then we would with a normal smooth surgical procedure as a result. I also suspect that your veterinarian used a larger size suture material, possibly a nonabsorbable one, to make sure that the surgical site stayed closed. That also will create more scar tissue.
To help reduce the scar tissue and help healing I recommend warm compressing the incision area at least twice daily and then gentle massage of the area with an antibacterial ointment like polysporin or Neosporin. You can also apply vitamin E to the incision areas. Puncture the capsules and dribble the contents on the incision.
I also recommend oral omega 3 fatty acids. They are natural anti-inflammatories and improve skin and tissue health in general. Use a dose based upon the EPA (eicosapentanoic acid) portion of the supplement as that will balance the rest of the supplement properly. Give 20mgs of EPA per pound of body weight daily.
Once the incisions have healed all the way through (have your veterinarian confirm this) you can also use cortisone ointment on the scar tissue to help reduce inflammation and thickness.
Best of luck with your fellow, please let me know if you have any further questions.