Have infection in wisdom tooth extraction, 2 months, antibiotics aren't helping. getting drained tomorrow. what happens in this procedure?

Pressure relief: Accumulating fluids are typically the source of pain in dental infections so drainage is often the key to prompt relief. Once symptoms are reduced your treating doctor will make a diagnosis and develop a treatment plan that may involve additional surgery or medications or not, depending on what presents. Be sure to ask that person as they will be the source of your best answer.

Drainage of the pus: will help clear away the local infection faster. Once the pus is drains the antibiotics will act better, faster and the healing will be achieved. Best of luck!