Get it checked out, my husband had a lump under his arm and it was getting bigger we thought it was just an infected node, even the doctor did, they did a biopsy and he has melanoma! It's a tumor and they don't even know where the starting point of the cancer is, so be safe and get it checked NOW. We have a long road ahead of us, wish us luck :)
Hi,
The lump in your armpit may be caused by shaving or use of antiperspirants, bacterial or viral infections, vaccinations, benign cyst, lipomas, and even cancer. Have this evaluated further by your doctor for proper management. Your complete medical history, physical examination and some tests will help determine the underlying cause.
Take care and best regards.