What Is The Sore On The Side Of My Face With Pus Discharge?

I have a sore on the side of my face in between my mouth and below cheek that has been here for about 2 months. It starts to heal and then it starts to itch and it will have blister-like or pus like come out of it. I have been on bactriban and zovirax but it will not heal up completely. What is this. It burns quite a bit and I put an ice pack on it to relieve the burning which comes back.