It could be due to Erupting Wisdom tooth, or cheek bite. Need to know full history before diagnosing anything. Attach photographs or x ray if you have. Gel will give you temporary relief only. Consult doctor online or offline for better guidance and treatment options. Warm saline water rinses two to three times a day, use mouthwash.

Hello... If you think it is because of cheek bite then it would keep coming time and again...you can’t keep using gel every time. Because a constant trauma would lead to infection there. Visit a dentist reach to its cause and get it treated.

Hello  , Please visit dentist for   investigation and diagnosis..as of now you can go for warm saline gargles.. You  can apply  dologel CT on affected area..

Hello, Please share the picture or X-ray of affected area so that I can diagnose better! For ulcers ,you can use this get for the relief but check if your metabolism is good. Drink more water,have a healthy diet!