If you have cracked a bone, it will take 6 to 8 weeks to heal.
If you have pulled or torn intercostal muscles, it will take 6 to 8 weeks to heal.
Every time you re-injure during that period, reset the clock to zero and start over plus add to the chances you are creating a chronic injury.
Dude, 8 weeks out of a lifetime is NOTHING especially when we are talking 8 weeks of zero to limited training (as opposed to, say, 8 weeks of chemo, 8 weeks of living in a tent in the snow, pick your personal or societal disaster).
Having said that.... you may check with your instructor about doing just the nage side of the training, moving very slowly focusing on breathing and fine details, doing weapons kata, etc. It need not be all or nothing.
You are looking for good advice ? Here it is from Janet, a person that knows what she is talking about...Take it from an old timer that ignored good advice so many times, remember one thing, as you get older all those old injuries will come back to haunt you..
Take time out and heal.