Develp a small lump which was having pus near tonsil.took antibiotics it got shrink&no pus but shrinkedpack still there?why?culture:staph aureus

Depends: If you actually do have a small abcess it isn't unusual for it to shrink but not resolve with just antibiotics. Often it has to be lanced (cut open) to drain and completely resolve. Alternatively, it may actually be just a 'crypt' which is an area of food and mucus accumulation in pockets often found in tonsils. The surrounding area may have been infected and now just the crypt material remains.