Thanks for your query, I have gone through your query. The bump over the gums below the tooth is because of the abscess or collection of pus secondary to teeth or gum infection. Consult a oral physician and get it evaluated. If I am your treating doctor, I would have suggested you to take radiographs like RVG or IOPAR to rule out gum and teeth infection. If it is a gum or teeth infection i would have prescribed a course of antibiotics like amoxicillin and metronidazole (if you are not allergic). Then i would have suggested to go for scaling and root planing for gum infection. RCT or extraction if it is a tooth infection. I hope my answer will help you, take care.