It sounds like you have a soft tissue infection, which you should discuss with your primary care physician
. These are usually caused by bacteria that live on the skin. Staph is one of those bacteria. From a physicians point of view, staph comes in a few different types depending on what type of antibiotic works against it. One type that you may have heard of is MRSA (stands for methicillin resistant staph aureus). Whenever you treat a soft tissue infection, you have to make sure that MRSA is covered. That is why your doctor
put you on bactrim pills. Bactrim covers community acquired MRSA.
The real question here is whether or not you have an abscess
. Staph is known to cause abscess and when it does, the antibiotics alone will not cure the infection. The abscess must be drained. This is what your mom tried to do when she lanced it. If an abscess is there and no puss or fluid came out, then you will likely need to have it lanced again by a physician.
I suggest that you schedule an appointment with your primary care physician. He or she can again look at the infection and determine if an abscess is present. If there is one, then it needs to be drained. If there isn't one, then your infection should get better with antibiotics.