if you defeat drowzee in viridian forest, is there no other way to get drowzee again? is there something im missing here or do i have to restart?

i dont know...

Walk into the Inner Sanctum in the Distortion World - that's why you get sent there. Drowzee will be waiting for you once you enter, no matter if you go immediately after defeating it in Viridian Forest or you wait 5 years! She'll be in the Inner Sanctum when you arrive.

Is there a way to go back if i left ._.