My Husband Has Had A Squamous Cell Cancer Removed From

My husband has had a Squamous cell cancer removed from his scalp. It was about 20 stitches and we are in and out of the Hospital seeing the Doctor every 4 to 5 day during this last month! It is open the size of a silver dollar and he just had the stitches out on Friday but the center is still open and just underneath is his skull bone. It does not seem to be healing correctly, I fill it with an antibiotic cream and change the dressing twice a day but it is worrying me. Can you tell me anything that may help?