My Son Had A Skin Graft On 18th Oct. When

My son had a skin graft on 18th Oct. When he removed the dressing 2 days ago was surprised to see there were stitches that skin had partially grown over. The wound now is completely red, and quite swollen. (He is sending me photos and tells me he hasn't time to go back to the hosp. I`m in a different country.) I am telling him to get it seen to asap - looks like a massive infection to me. Can you please advise me as to what I can tell him to force him to get it seen to, please.