There needs to be a secure recovery method.
There are - but it's too late for your lost Notes password.
It's distressing I know when you can't recall a password, and the human memory is useless at recalling the myriad of passwords we need to have. I use secure software to recall all the information I can't recall. Alas, there is no entry into a locked note.
From: How to lock notes on your iPhone, iPad and iPod touch
To unlock a note, you need to enter the password that it's locked with. If you forget the password, Apple can't help you regain access to your locked notes. You can create a new password, but this won’t give you access to your old notes. A new password will let you password-protect any notes that you create going forwards with the new password.
But you can prevent this happening again with something like one of these software packages:
1Password
mSecure
My Eyes Only
Keeper Security
Last Pass
and there are many more.