Bumps that appear under the skin around the groin area may be enlarged lymph glands, according to Medline Plus. Ingrown hairs also cause bumps in the pubic area, according to WebMD. Painful lumps appearing suddenly are most likely caused by an infection or injury of some type.
Deposits of fat cells under the skin known as 'lipomas' appear as bumps under the skin, but are not harmful unless they cause pain or discomfort. Cysts, abscesses and some cancers also cause bumps and may occur anywhere on the body. Most lumps under the skin are not cancerous, particularly if they feel soft and roll under the fingers when pushed, according to Medline Plus.