Looks like you are suffering from Periodontitis which is inflammation and possibly infection of the gums and the attached tissues. Use a mouthwash containing Chlorhexidine 0.2% or 0.12% to rinse mouth 3 times a day. (Example brands are Hexidine, Clohex ADS, Periex, Hexide etc.) Massage an astringent (Example Stolin Gum Paint) over the affected area. Also do warm saline mouthwash once at night and avoid cold, refrigerated food items.
Next Steps
As soon as possible consult your dentist as these are temporary measures.
Health Tips
All Brand names are suggestive and not binding.