I see a white mass in the socket where my wisdom tooth was removed.

In most cases this is normal healing. A white film seen about 3 to 7 days after an extraction is usually granulation or epithelial tissue forming new flesh, so do not touch it with your tongue or fingers or try to pull it off. It can be mistaken for food debris; if it stays firmly in place after a gentle rinse with water, it is most likely healing tissue. However, if 1) pain gets worse 3 to 5 days after the extraction, 2) the socket looks empty, and 3) bad breath and an unpleasant taste come with it, it may be a dry socket in which the blood clot has been lost, so come in right away.