What Causes A Red And Inflamed Lesion On The Cheek?

Hello, I have a question for my mother. She has a large lesion on the left side of her cheek. It is now bigger than a silver dollar, swollen, red and inflammed and she says it is very painful. She has no insurance so no way to consult with a doctor. Any ideas on what this could be?? She said she pulled a hair from the area 2 days prior to this. Please help!