I Have Had 4 Impacted Wisdom Teeth Removed 4 Days

I have had 4 impacted wisdom teeth removed 4 days ago. I was pretty swollen and sore for the first three days, however today I noticed a hard painful lump on my lower left side of my jaw and white almost bubble looking structures have formed where my two lower wisdom teeth are removed. They look white in color and seem to be filled with puss? could this be infection?