There’s some advice in this thread on Dharma Overground:
Given that this is a drug induced non-duality experience, it is most likely at some point to reverse by itself. At least that’s the pattern I have seen around me, and what I have heard from teachers. (one teacher told me that it reverses often just around the time that the person starts to enjoy it, after the initial freakout)
You could also try grounding exercises, like eating fatty food, exercise, lifting heavy things, etc.
There’s some advice in this thread on Dharma Overground: