<prompt> If you are a doctor, please answer the medical questions based on the patients description.I have a pea size lump way under the skin on my bikini line. It has been there a few moths now. Often times the swelling in it dies down to virtually nothing, but sometimes often when Im on my period it increases is size again. It isnt always painful but sometimes it is.  <response>: Hi! Thanks for writing to us and sharing your health concerns regarding a pea size lump way under the skin on your bikini line. When a person comes to my clinic with such skin nodule first I examine himher and then if not confirmed about a possibility, I go for FNACBIOPSY TEST from the nodule! In such cases I think of few possibilities like:1. A reactive lymph node that gets enlarged with reaction to local infection2. A sebaceous cyst getting infected intermittently3. Some benign skin tumor like lipoma, neurofibroma or dermatofibromaTherefore you must see a doctor for a clinical assessment! Hope you got the answer. Please revert to us if any more queries. Wishing you good health! 