Comedian Pete Davidson opened up about his recent rehab experience and ongoing use of marijuana during a stand-up show, “Pete Davidson: Rehab Tour,” on July 20. Davidson shared that while he has overcome addictions to cocaine, ketamine and various pills, he still uses marijuana. See Also: Fans Baffled As Pete Davidson Abruptly Cancels All His Shows Until 2024 “I can’t quit [weed] yet. It’s all I have left,” the 30-year-old said, reported the Daily Mail. “I did coke and ketamine and f–king all the pills and all that s–t. All I have is weed left, so it’s almost over, but I’m holding on for a lit…