Since when is the lump? Is it painful and tender? Are you diabetic?
It looks like to be either of the following;
1) Boil or carbuncle
2) Folliculitis; infection of the hair follicle
Usually they need treatment in the form of local antibiotic creams and oral antibiotics or some incision drainage procedure.
With a family history of diabetes you should get a glucose tolerance test and glycosylated hemoglobin (shows last three month average blood sugar) to rule out diabetes, once again.
Please feel free for your follow up questions.