How Can A Sensitive Spot At The Underarm After Laser Hair Removal Procedure Be Managed?

Hi. I had laser hair removal on armpit on Tuesday for the second time. No issues but yesterday I had a sensitive spot in my pit and when I touched it I found a pea sized lump. This hurts more when pressed and this morning is causing a dull ache and hurts more if I lift arm above my head...? There is nothing to see tho? Can you advise?