Small bumps under the armpit scratched one now they have spread under the armpit now a lump has formed under the arm isthere any home remedies

See your physician to determine what the lump is, what the small bumps may have been.

It may only be an infection. You can dab it with oil of lavender or Hydrogen Peroxide. You may be allergic to something in your antipersperant. But show your doctor because it could be something needing treatment or a medical prescription.