Most lumps and swellings under the skin are harmless and can be left alone.
Unexplained lumps or swellings under the skin can occur in the following areas of the body:
- Neck or throat
- Groin area
- Anus (bottom)
- Hand, wrist or finger
- Shoulders, back, chest or arm
A painful lump or swelling that appears suddenly over a day or two may be caused by an injury or infection. It’s likely to be an infection if the skin around the lump is red and warm.