Hi
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From your description it looks like that this person has developed keloids on the scar tissue. This can itch and look like tags. Treatment is surgical excision or even cryosurgery. Please ask this person to consult his surgeon. Take care!
I would go see your doctor, or possibly the surgeon who did the surgery. It is rare to do an umbilical hernia without mesh these days, unless it is a tiny hernia. While unlikely, after all this time, it could be an infection of the repair. It is also very possible that it is an infection completely unrelated to the surgery, but either way it should be checked out.