A 34-year-old man presents to the emergency department with a 3-day history of worsening dental pain and swelling around the left lower jaw.

The swelling has increased gradually. He is able to swallow normally and has no voice change, drooling, trismus or difficulty breathing. There is no periorbital swelling.

On examination, he is alert and comfortable at rest.

 Temperature: 36.8°C 

 HR: 84 beats/min 

 BP: 128/76 mmHg 

 RR: 16 breaths/min 

 SpO₂: 98% on air 

There is a localised, warm, firm swelling adjacent to a carious lower molar. The swelling is tender but there is no floor-of-mouth elevation or tongue displacement. He has no rigors, lethargy or clinical evidence of dehydration.

What is the single most appropriate management?