You should be in regular contact with your surgeon and he should give you dressing changes to perform daily to help encourage the wound to heal from the inside out. He/She may need to excise any non-viable tissue (black scab like material), which can be done as an in-office procedure in most cases. You may need a scar revision 9 months - 1 yr after it heals to make the scar more cosmetically appealing. Good luck!
First of all: go see your surgeon. Every week until its healed. Follow your surgeon's directions to the letter this time. No smoking.
The black tissue needs to be removed - either with frequent dressing changes or by your surgeon trimming it off. The wound can then hopefully heal in. A scar revision can be performed at a later date to make it look prettier.