If the ulcer is localised to a specific site, visit your dentist whenever it happens next. Until then follow the instructions given by my colleagues.

Hello sir, There are many reasons for constant and recurrent  ulcers .. it varies from dehydration , malnutrition, stress, sleep less Ness , working environment, iron deficiency or it may be due to sharp or rough surfaces on the tooth or malpositoned tooth.

Avoid hot and spicy food..get vit b12,zinc,iron,folic acid tested...apply dologel in affected area

A constant ulcer on the gum can be a sign of localised gum inflammation which is most commonly due to lack accumulation in that area and can also be due to other secondary factors. A proper clinical examination will be required to make the right diagnosis so that the right treatment can be suggested. The duration of the ulcer is too long for it to be ignored further and a detailed clinical history about your habits such as tobacco usage as well as history of medications needs to be discussed. Regards.