Bactrim effectiveness for skin infection/swelling

Patient: How long should you see results while on Bactrim to know if it is effective? I am taking it because I had swelling due to an infected pimple on my arm, the doctor drained a small amount from the pimple and placed me on Bactrim 2x day for 7 days. This is my second day 3x doses so far and my arm is still red and warm with slight swelling and discomfort. I do not have a fever or anything, the pain is mild and localized.

Symptoms: Redness to area, mild swelling which makes it uncomfortable to even use both my arms to fix my hair, mild pain, and warmness above area. The area is also on my elbow, sorry i did not mention that earlier.

Doctor: Thank you for your question. You are very early in the antibiotic treatment of your skin infection. You can likely start observing improvement around the 4th to 5th day of this course of antibiotics. It is important to note that you need to complete the entire course of antibiotics even if your infection is completely resolved. It is also important to note that antibiotics continue to work for days after the course is completed.Thank you for consulting