I had this issue before 2008 , In my case my dentist adviced me to visit him for every 3 months and he carried out some procedures .
Gum inflamation root cause might be different so ask your dentist
It took almost 2 years for me to resolve my gingivitis issue , now i use to get checked out personally every month as well as by the dentist in 6 months .
It can took many months to treat gingivitis
As my dentist showed me to check mouth , throat , palate , tongue , glands , cheek , teeth , gums etc
Clean hands , look into mouth for white areas which seems skin is erosive , red lesion with erosion and easily bleeds , some red lesion blanch on press so they need not immediate attention most of the time
Palpate the floor of mouth , cheek , palate , glands on extra oral palpation used to be discharge watery thing more when they are normal etc .