Tape it up. Athletic tape and KT tape can be your best friend. KT tape can relieve pressure and help range of motion. Athletic tape can help support strained joints such as the wrist or ankle. This will allow you to still be able to train instead of taking a few days hiatus. We all know taking unexpected breaks can make one feel grumpy!
Drill only. Instead of going 100% rolling, drill a technique instead. This can help prevent further injury while still allowing you to get 1% better. This can also help you work on a specific type of game you also might have been neglecting. Is your ankle strained where you can’t pass? Work on your guard, instead.
Go to class anyway, even just to watch: If you are sidelined from any kind of activity, I encourage you to visit your BJJ class for a couple of reasons. To keep the routine of showing up. Once a routine is broken, it can be very easy to back slide. By watching techniques and writing them down while on the side can help you from maybe finding a detail you haven’t noticed before.
Watch techniques at home. Also, you may find strength in the encouragement of your teammates. I know some hate the idea of watching others roll while they are sidelined, so this option may not be for everyone. Instead, maybe go home and watch some BJJ on YouTube! or if swim, jog, or lift if you are able too. You can find out how to perform a swinging neckbreaker or something more lighthearted like how to levitate.
Check with your doctor. Your doctor should be able to tell you whether it is safe to train or not and your capabilities of what you can do. Do not neglect any kind of recovery methods while training injured. Recovery is an important part of training that is often forgotten about even when not injured. Do not take this as medical advice, but as helpful tips to keep you on the mat, either mentally or physically.