Gum ache

[Mariz]

Swollen and painful gum at the last molar inside the mouth
The tooth is not yet developed and its being covered with gum

 

[MattKW]

Sounds like pericoronitis (inflammation around the crown), often associated with slowly erupting or impacted wisdom teeth. Clean it as best you can, get a chlorhexidine mouthwash ("Savacol", "Periogard") . Usually goes down after a few days. If not, go to dentist for ultrasonic cleaning and possible antibiotics. If associated with a wisdom tooth (3rd molar), it's usually time to think about having it extracted.