Cellulitis. Cellulitis is an infection of the skin and underlying tissues and is usually treated with antibiotics and sometimes requires debridement, which is a removal of the devitalized or dead tissue from the area. It sounds as though you are describing a ulcer when you speak of a "hole" in the area. This type of deformity may remain or partially fill in. A photograph would be helpful.
Cellulitis & hole. The deep hole is most likely a skin ulcer, which is a different problem from the cellulitis. Cellulitis will respond promptly to an antibiotic. The skin ulcer is usually caused by excessive pressure on the skin, often from inadequate venous flow. These take time (weeks to a couple of months) to heal and require careful dressing changes.