Hi,
I would suggest you to take it seriously since the lump has been there for a long period. I would suggest you to visit a physician/surgeon and may be a biopsy will be required. Only a biopsy will be able to tell the exact nature of the lump. In biopsy, a small sample of the tissue is taken and examined under a microscope.
Please do not delay it further.
I hope that helped. Please do keep me posted.
Kind Regards.
Each person likes to have privacy but sometimes encouragement is a good idea.
Months is not a good sign of the possiblity of it going away. It deserves at least a check
If it seems to be on the skin level, then encourage a dermatologist.
If it is below the skin, it would be a good idea to get it checked by an internal medicine doctor.