Nikki Sixx, the co-founder and bassist of the rock band Mötley Crüe, had gone through multiple stints in rehab during his life to battle drug addiction. Since I do not have access to real-time information, I cannot provide details on what specifically happened to him after he left rehab in any particular instance.
After going through rehab, Nikki Sixx has been known to focus on his music career, as well as on his personal growth and recovery. He has often been open about his struggles with addiction and has used his experiences to raise awareness about substance abuse issues.
For the most current information on Nikki Sixx's life and activities after rehab, I recommend checking recent news articles or official updates from his social media or website.