Knowing a scale means two things:  understanding the scale degrees & being able to make music with it.

As a beginner knowing one basic scale pattern for any given scale & being able to play melodies with it are as much as you need.  If you understand the pattern, the scale degrees & can make music with it then you are doing fine.

As you gradually improve these two things will also guide you in knowing when to add another pattern of the scale, learn a different scale, or move up & down the fretboard, learning different patterns & positions of that or any scale.

Let's take your example.  You've learned the B blues scale.  Do you know all the scale degrees in the pattern?  Can you play a bunch of licks with the notes of that pattern?  If not, then spend time doing that.  If so, then you can add the next pattern up the fretboard. 

Many beginners learn a scale as a visual pattern of notes to play, but nothing more.  And that's a great place to start!  But then you need to start working on understanding why you are playing that pattern.  Why that shape?  Why those notes?  So, you learn the scale degrees to really understand the sound of the scale & what you can do with it musically.  And the best way to do that is to use the scale to make music.  Learn licks & riffs with the scale.  Learn to hear the sound of scale in your mind before you even play the notes!

This tutorial is in G, but it will show you various ways to make music with the pentatonic shapes.

https://www.guitartricks.com/tutorial/1147/

This tutorial is in A, but will show you how basic blues scales can be moved all over the fretboard to make a variety of licks from just a few shapes & patterns.

https://www.guitartricks.com/tutorial/2380/

Hope that helps!