Thank you and welcome to HCM
From your description you are presenting with a hematoma
or an abscess. A doctor will need to take a closer look at it to evaluate. Do you present with any other symptoms like fever, chills, joint pains
etc which could be signs of infection. For now, you will require an antiinflammatory such as aspirine ( which has thrombolytic properties too) in order to take care of the pains. Then revisit your dentist
as soon as possible. It might require incision and drainage
if pus collection or blood collected in a cavity.
Hope this helps