What can be done for a gaping hole where a cyst was removed and it opened up?

A couple of days after the stitches were removed, the wound opened up. The hole is about 3/4 of an inch deep so it is a big gaping hole. The doctor told that he could not reclose it because it could get infected. He said to pack it with a damp gauze twice a day and keep a bandage over it. That the hole would fill up in time. About 3 weeks according to the doctor. It has been over a week and it doesn't look any different. We are worried that it won't fill up. Is there anything else we can do for it?