What Does A Painful Lump In The Armpit Indicate?

I had a bump that appeared after I use a cream to remove hair from under my arms. On one arm pit it appeared a risen. It became very sore. I called my doctor, talk to my nurse, she told me to use a warm compress and if that didn t work come see the doctor. It did not work, in fact, went to the doctor and was told I had some bacteria set up. given antibiotic Clindamycin to take and come back on the 20th. My concern, it seems I feel some more bumps right under the skin. Should I be fearful?