Published: Apr 06, 2010 7:47 PM EDT

AUGUSTA, Ga. - Tiger Woods says "nothing's changed" on the golf course and he still expects to win the Masters in his return to competition after a devastating personal scandal.

Tiger Woods began his comeback with an extraordinary 35-minute news conference at Augusta National on Monday, taking full blame for the personal failings that led to revelations of multiple extramarital affairs.

Woods refused to say why he spent 45 days in rehabilitation, but says he intends to continue with his treatment. He also said he received five stitches in his mouth after the infamous Thanksgiving night car crash outside his home, but stressed that he's not addicted to prescription drugs.

While his wife, Elin, won't be joining him at Augusta, Woods still believes he can win his fifth green jacket after a five-month layoff.