What do you do if you need to take time off if you’ve injured yourself or over done it a bit?
Well, firstly, take comfort that learning is still taking place away from your instrument. Think of your practicing as data input, not getting better in real-time. Your brain processes that data fully when you sleep; and not necessarily in a single night's sleep. Sometimes too much practice actually overloads the brain, so time off gives it a chance to fully integrate the data.
Thinking of practice in this way also takes a lot of pressure off you, and allows you to enjoy the process more with less frustration and it's accompanying tensions.
And secondly, you can do what bass legend Jaco Pastorius did and what I'm sure you've heard sports coaches recommend. The brain doesn’t differentiate between real and imagined movement well, so you can rehearse the movements purely mentally. This is still a hot topic in scientific research, it used to be believed that real and imagined movement was processed the same, but recent research has shown that the lack of sensory input during imagined movement means the processing isn’t exactly the same , however, that doesn’t prevent it from still being very useful to our purposes here. As the author Donna Tart said “what is unthinkable is undoable”, the opposite is equally true. Jaco has stated in interviews that's how he practiced when touring and his bass wasn't to hand, for example whilst travelling between gigs. He joked people thought he was just spaced out, but he was doing rigorous mental practice.
If you can read music or tabs, time away from the guitar can be still be put to good use working on learning new repertoire. An additional advantage of this is that practicing in this way is associated with physical ease, and is of itself, practicing ease. One thing that's often said about virtuoso's is that they make it look easy. Well, if it wasn't they wouldn't be able to do it. But the thing that's usually missed is practising actual ease to replicate the virtuoso's experience. Practice ease itself. When learning a new piece or technique ask yourself how you want it to feel to play it.
If you happen to play slide guitar you’re on to winner, you can keep working on your musicality on the guitar without stressing your fretting hand. If have a long standing injury why not add slide to your repertoire of skills to keep your interest in guitar ignited.
It goes without saying really that plenty of Constructive Rest is a must, but after some time off, reacquaint yourself with the guitar gently.