Scab fell off my wound from surgery after a bath. It was yellow/green. Can see stitches now through the "hole" left behind. Is this normal?

Call your surgeon. The sutures that your are seeing may be absorbable sutures that "dissolves" over several weeks. If you have redness, increased pain, fever, or pus like drainage see your doctor right away as you may be getting a wound infection. As far as the "hole" I would keep this area clean and dry and covered with a sterile gauze. Do not let moisture get into the wound. Ask your surgeon!