Why does the left side of my mouth still hurt after seeing a dentist and being on antibiotics for a month? cant see dentist cause they keep cancelling

Treatment?: Without an exam or knowing what treatment was rendered it is hard to answer your question. Seek asecond opinion if you can't get an appointment.

Signs of Infection: You have an infection and you should contact your dentist immediately for definitive treatment ensuring the infection does not spread or lead to additional complications.

Find new dentist: If they keep cancelling I would find a new dentist. repeated cancellation via dentist or patient is unacceptable and since you are still in pain I would search for a dentist that is willing to be there for you and committed to your oral health