Training while injured

I injured my shoulder a little bit ago and gave it some time to rest. I decided to go for a chest day today and felt extremely weak and didn’t get a good workout in. My reps were low and I just didn’t get a good pump.

I’m worried my shoulder is going to take a few months to heal well enough for me to get back to full function.

What do I do in the meantime? I don’t want to lose gains because I stop training for a few months. But I don’t want to prolong this injury or make it worse. Any advice is helpful.