Is Bone Grafting done immediately after the infected tooth is extracted?

Every Situation is different.  Every surgeon has their comfort zone as well.  Infection in the extraction site is not a definitive contraindication for delayed bone graft.  I routinely graft the socket of extracted teeth even if there is some infection present.  The extraction site is prepared appropriately removing all infection until clean, the socket is then grafted using bone and an appropriate membrane if necessary.  The 'Pimple" you describe could mean there is a "hole" in the bone in that region where pus was draining.  this tissue needs to be removed and a membrane placed between the graft and surrounding tissue in order for it to heal.  The time of extraction is the best bet to get a good grafting result, otherwise a much more significant graft will need to be done prior to implant placement.  This is based on my experience only, but I have performed it several thousand times.  I would NOT place an immediate implant in an infected site though.  Grafts will heal as long as done correctly, but an implant will get infected about 50% of the time.In my office you most likely would have the graft done then delay the implant for 3-4 months 

If there is active infection the day of the extraction, then you will NOT be able to have grafting done the same day. I would imagine the periodontist or oral surgeon would want you to be on antibiotics at least 3 or 4 days prior to the extraction. Ask your surgeon these questions.