Some thigh lifts place scars only within the crease in your groin area. Others have s scar that runs down the inside of the thigh down to the knee. I am assuming that your procedure was the first one with the scar in the groin crease. If you had a reaction and poor healing, then the scar will likely be wider than it was intended. It is quite possible that this scar is visible outside of a bathing suit. In order to correct this, you might require a scar revision.
However, it would be important to try and understand why you had the reaction in the first place. Do you have an allergy to one of the sutures used? Did you develop an infection? The only way to know is to look through the operative report and see what was done and what sutures were used. Then, seek out a good plastic surgeon who can assist with your revision. Good luck.