This is a big island, and the swamp makes up a good chunk of it - might be worth exploring.
Ah, a friendly swamp monster. Interesting fella, shame that he can't grow a moustache.
Yeah, how hard could it be to grow a moustache naturally?
Yes, obviously you'll need to help somehow.
Have you found all twenty flowers?
Have you found nineteen flowers?
Then this guide would be a good place to start.
And if you want to know how to get the twentieth, follow this guide.
You should also have Malthe's Cocktail Bible! Maybe one of the entries might be useful?
That's right, "Michael Hair Jordan!" And the cocktail machine has what you need.
You need three ingredients to make the Michael Hair Jordan.
Ingredient 1 (Base) - ? Ingredient 3 (Flavor) - ?
Whiskey, AKA "GlenModrig 18 Year - Whiskey"
Coconut Milk
If you don't have a tomato yet, remember to finish your errands.
Deliver the flowers, silly! This guide tells you what to do next if you're struggling.
Return to this guide after finding a tomato.
Great, you should already know what to do then!
Ingredient 1 (Base) - ? Ingredient 2 (Modifier) - ? Ingredient 3 (Flavor) - ?
Then just pull the lever for your cocktail!
Tomato
The cocktail bible might be able to tell you what it does.
Right where the sun doesn't shine - the swamp!
Put the cocktail into the liquid that the swamp monster is drinking.
The swamp monster left something behind.