Does Bactrim treat boils?

This person says yes;
My doctor gave me Bactrim for serious boils that developed in my underarm, the medication worked wonders
So I'd say yup.
God is good

Hi, Yes it will help you.

Bactrim (sulfamethoxazole/trimethoprim) is a prescription antibiotic approved to treat a variety of different infections. In addition to treating infections, it is also approved to prevent one particular infection, Pneumocystis carinii pneumonia, in people with a weakened immune system.

Additional information

Always seek professional medical advice about any treatment or change in treatment plans.

Watchful waiting - boils will often self-resolve.
Surgical lancing and drainage
Antibiotics
Good skin hygiene
Avoid picking at the boil
Avoid squeezing the boil
Warm compresses
Heating pad
Antibiotics - if there is surrounding cellulitis, multiple or recurrent boils
Mupirocin ointment to the lesion and nose - for recurrent boils
Ichthyol
Antibacterial body wash - for recurrent boils

Take care and good luck.