Getting the potion

Introduction

Since you picked your mushroom yourself, you must also prepare the potion by yourself, as a safety measure. This may seem strange, but it is possible you have contaminated the mushroom while carrying it, as you're not a herbalist. But don't worry, I'll help you.

Cunclusion

This looks perfect. You can use this potion to leave the island. I would show it to Ilia if I were you.