I Have A Very Large Wound Over My Left Knee

I have a very large wound over my left knee on a wnd vac . I have developed a periwnd cellulutus at the 6 oclockk position in the periwound area. 10 days ago.the doctor put me on Clindamycin. But the cellulitis is not better. It isn't very painful unless pressed by hand . Im concerned because it is not better and my surgeon will not pursue a skin graft till cellulitis is resolved