I'm hesitant to tell my neurologist about substance use, it's my first time meeting her. how can i explain properly without being judged like before.

You cannot: Doctors are people with varying opinions when it comes to social norms. There's likely nothing you can do to ensure acceptance, but I would suggest answering honestly but to-the-point, and unless asked to elaborate or unless it's relevant to your medical complaint not to attempt to explain substance abuse or dwell on it which may detract time from more important parts of your evaluation.