I have a bump/boil underneath my arm, armpit, its swollen, red, painful. there was a bump that started out in the beginning of september, i went to the er & got put on an antibiotic, it went away, now im seeing & feeling the same thing coming back?

Follow up is needed for a diagnosis and having proper treatment going forward. Establishing with a primary care doc will help greatly as otherwise you will only have episodic treatment, expensive and time consuming. Hidradenitis suppurativa is a chronic skin disease that appears likely in your case and that will have to be managed properly.

Agree with Dr. P. Hidradenitis suppurativa is a consideration. Visit this site for information and see your doctor for continuing care: https://www.nhs.uk/conditions/hidradenitis-suppurativa/#:~:text=Hidradenitis%20suppurativa%20(HS)%20is%20a,%2C%20bottom%2C%20breasts%20and%20armpits.