Deryck Whibley -- Alive But Wasting Away in First Pic Since Near-Death Experience

Sum 41 frontman Deryck Whibley is a shell of himself -- looking shockingly frail today as he leaned on others for support ... days after admitting he nearly died from years of hardcore drinking.

Deryck had to be held up by two women during a walk in Los Angeles.

On Friday, Deryck revealed he'd been laid up in a hospital bed for a month, and confessed on his blog... "the reason i got so sick is from all the hard boozing i’ve been doing over the years. it finally caught up to me."

Deryck says his liver and kidneys collapsed, and docs have told him if he has one drink he will die.

The damage is obvious when you remember how Deryck looked in his heyday with Avril Lavigne.