Red swollen montgomery gland/bump on the aerola, not pregnant. what could this potentially be? thanks

Infection: These are often minor infections by simple skin staph that enters from the surface. Moist heat can often bring these to a head so they drain spontaneously & self resolve. A moist towel placed in a zip loc bag with a few holes & microwaved briefly is a simple warm compress. Several applications/day may resolve this. If not it may require prescribed meds or other procedure.