Hello and welcome to HCM
The descrption you have given suggest that you are suffering from a boil or furuncle
When the hair follicle is damaged by a scratch or other break in the skin, the bacteria is able to move deeper into the follicular tissues, causing an infection and resulting in a boil. Boils
more common in diabetic and obese
I suggest you to see a surgeon immidiately , start antibiotics, he will drain it or do a FNAC to rule out cancer which is less likely in your case.
I hope i have answered your queries.
wish you Good health