A largish lump under the incision line seems to be a pocket of pus and ,if it is so,it will need a surgical drainage
The repeated infections indicate poorly controlled diabetes
You must make all efforts to keep your sugar levels in control to avoid future complications.
You already had a CABG,which makes all the important for you to keep your sugar,lipid and blood pressure in tight leash.
has no connection with this lump.
600 mg for pain whenever required.
Consult your surgeon as early as possible.