Stitch spit up 2 montns after TT. Doctor put an acid inside the hole and it's been draining yellow mucus. I am scared. (photo)

After 2 months of having my tummy tuck done my stitch spit up and made a whole, it Keep draining and 3 days ago I finally got to see the doctor and he put an Acid inside the little whole and It has been draining a mucus of color yellow, I am very scared but I don’t have fever, the area is not hot either, he says that he will stitch me back in two weeks if it doesn’t close, but if he put that acid inside what is for? I know I should ask him, he just told me it was gonna burnt and it did.