Banged my knee up pretty bad competing yesterday. The most important thing to do upon injury is to ensure skill degradation does not begin. This is one of the few times I really value non resistant drilling. Maximize your mat time in any way that you can. In terms of live training I will do something as simple as hand fighting from static positions such as kneeling vs seated guard, mount, side control and potentially standing vs standing if I have a trusted training partner. There's never a valid reason to not improve during an injury. If you are completely unable to drill or do any sort of simple task training on the mats then, it is time to study as if you have BJJ final exams coming up. If you come across an injury, I hope this short post sheds some light on your options to progress.