Probably an abscess - an ulcer ... If the ´state of that lump does not change within a few days, buy Vishnevsky's ointment (black ointment), instead (for example at night) lubricate and cover with leukoplasty (so that the ointment does not rub off and can work) . Alternatively, see a doctor - you won't ruin anything, but I think it would be an unnecessary "alarm". ;-)