It seems that you have an episode of infection in the legs, this is a super-added on the pre-existing chronic venous insufficiency. As you are obese with weight of 110 kg, the chances of developing maturity onset diabetes are also high, though on this occasion the high sugar levels were more of stress-induced hyperglycaemia. I believe that the doctors treating have done a good job by controlling infection and the fact they are thinking of skin grafting is an indication that the healing process is progressing well.
Regarding operation for varicose veins I do not think it is a good idea to operate while there is any chance of infection contaminating the operated area. I also feel that with present weight level anaesthetic risks are unacceptable. Other aspect of the problem is that the benefit of surgery for the varicose veins is much less when the patient is significantly obese. The only scenario for recommending surgery is in case the wound turns to a venous non-healing ulcer, in which case Saheno-femoral disconnection can be performed under local or spinal anaesthesia.
Ideally, you should lose weight and until that is achieved you should use compression hosiery (Graduated Compression Stocking).