The back of the head bulge a bag pressed pain should be inflammatory masses, that is, folliculitis secondary infection is very likely. The first thing you need to check is whether the bulge is red, swollen and painful, if it is caused by folliculitis infection, generally oral antibiotic treatment can be. Routine oral generation or second generation cephalosporins, such as cefradine or cefixime, can also be oral quinolones, such as levofloxacin or ciprofloxacin can be. In the process of treatment, if the mass shrinks and the pain is reduced, it means that the treatment is effective; if the pain of the mass worsens or if necrosis or suppuration occurs in the center, the abscess should be incised and drained if necessary, and the wound should be changed only then.