I have a non-painful hard lump in my armpit about the size of a pea. Its under the skin and sometimes its easy to feel and sometimes it seems like it disappears into my arpit and then I have to really press the area to find it.  Ive had it a little longer than a week.  Ive been applying wet warm compresses to it at least twice a day for the past 4 days.  How worried do I need to be that it could be cancerous?
Hi. Thanks for your query. Stop wet warm compresses with immediate effect. Armpit skin is very sensitive. This can be either a Lymph node as it is lost sometimes to be palpated. Sebaceous cyst is always attached to the skin and always palpable. The only way to get a proper diagnosis is FNAC, that is fine needle aspiration cytology, done if required under ultrasonographic guidance, or a biopsy. Is there is a lump in the breast ? Get this done and be assured, Whatever is the result this is treatable. IF infective just a few weeks course of an antibiotic and anti-inflammatory medicines, If cancerous treatment under the care of an Onco-surgeon and Oncologist.