Swelling and pain in gums are indication of infection. You haven't mentioned which tooth or tooth area are you having this problem. Is it related to your wisdom tooth area?
More precise treatment can be given after seeing your clinical pics or radiographs. Visit a dentist.
Next Steps
you need to visit dentist ASAP.
Health Tips
avoid eating hot and spicy food.
gargle your mouth with mouthwash after brushing.