Hello. Good day. Thanks for writing to HCM. I am Dr Praveen and I will be answering your query today. Since the lump has come about in a span of two weeks and its quite painful its likely to be infected. Skin conditions like these are quite commonly seen in patients with diabetes. Since you have been diagnosed with diabetes you need to know what type it is. If you are overweight with a family history of diabetes its likely to be Type 2 and you will need diet, drugs and exercise to control it. The lump will settle with better sugar control. Remember its a cycle...the infection will increase if sugars are high and sugars being high will cause an increase in infection. For the lump itself, please see a general surgeon. He/she may do and incision and drainage. An antibiotic like cloxacillin taken at 500 mg 8th hrly for 5 days should be enough. Wishing you good health. Warm regards.