A thorough history and physical exam would be helpful to assess that lump under your skin, which is why I recommend you see a doctor
. What is your age and gender? Do you have any other symptoms? Are you suffering from any medical condition or medication? According to the brief description you have given the lump, it does sound to be a benign lesion. Is it soft to the touch and usually movable? Most likely it is a benign soft tissue tumor known as lipoma which is composed of adipose tissue (body fat). These tumors can occur at any age, but are commonly found in adults from 40 to 60 years of age. They are generally painless unless they compress nerves. Your lump may regress but needs to have it taken out by a general surgeon
if it is bothersome or a cosmetic concern. Most of the times such lumps are harmless. Nonetheless, I would suggest that you get this lump looked at by your doctor in order to confirm the exact nature of it to rule out other malignant skin cancer such as melanoma and squamous cell carcinoma. Your doctor may order an ultrasound of that area to help in knowing its exact cause. Please consult with your dermatologist
soon who may refer you to a surgeon or order follow-up tests if warranted.