Hi, thanks for posting your query.
You have mentioned that your father had been operated in December.
Now the scar has turned red and itchy. Don't worry it is not due to side effect of operation or a big problem.
Your father seems to have developed a hypertrophic scar
or a keloid.
I shall try to explain you.
Normally, during healing,for 6 weeks more of scar tissue is formed and it becomes raised and reddened , then the scar matures which may take 6 months to a year when it tends to be flat and lighter. At times, surgical scars
may remain thickened to a degree and have more redness
than desired. We call this hypertrophic scar. Keloids
are formed due to deposition of thick fibrous tissue and extends beyond the wound margins. Keloids usually have a hereditary predisposition.
You may consult a dermatologist
for exact diagnosis and appropriate treatment.
Hope this helps you.