No matter what, taking a day off is going to put you back, unless it is a rest day. If you have an injury, you have to learn to train around it. If you can’t throw your jab, throw an elbow! You can always do something! You can change the intensity of your workouts, but you don’t have to skip training. Why sit on the couch and get depressed when you can just modify your workouts a bit and keep going!