Lil Wayne is off to prison. But first, dude needs to get his grill fixed.

After giving the judge in his weapons possession case a mouthful (har har), Weezy won a temporary reprieve from prison, where he was supposed to be sent today.

His one-year-term was to begin at today's sentencing, but it didn't. That's because Lil Wayne has to go to the dentist to fix all the bull$h!t going on in his mouth.

The judge won't throw him in the can until his surgery is complete.

GRILLED: The judge in Lil Wayne's case fought him tooth and nail.

But this will be the rapper's last oral (har har!) argument. The judge said no more excuses on March 2, when Wayne shows up for sentencing ... for real this time.

The frequent baby daddy was already planning a T.I.-like farewell, having sent one final message to his fans via his Ustream page: "Don't forget about me!"

On what was to be his final night of freedom for a year (he's now got 20 more), he told his online supporters simply: "I really, really, really, really love you."