Expert answer:
The location of a graft may have a rather unpleasant odor due to parts of the tissue that may have small areas of necrosis (bad smell is subjective in this case), but any changes in this case should be taken into account (smell, secretion, fever, redness). Three situations may be occurring: misinterpretation of that smell, graft necrosis (tissue death) or infection on site, need to seek medical advice.