Infectious MRSA abscess. You can really see the difference between a non infectious inflamed cyst and an infected abscess. From the outside they look similar but the infectious abscess is mostly firm inflamed tissue (the bodies response to infection-called induration). Extensive leukocyte accumulation from an acute inflammatory response to the bacteria entering the skin. Drainage of the pus pocket and the correct antibiotic and these generally dry up in 7-20 days. Sometimes they require packing but generally the pocket is much smaller than an inflamed cyst. Pus pocket. Juicy pop. Medical procedure. Incision and Drainage. MrPopZit.