hello and welcome to HCM forum,
i would like to inform you that the soft tissue
overgrowth may be linked to the sinus surgery
only if it was the same area where stitches were placed following the surgery.
I advise you to keep a check on it for pain,ulceration, bleeding or even size(if it is increasing).
kindly , see the doctor who performed sinus surgery,
i hope i answered your question,
i wish you good health.