Many survivors end up with "honeycomb" patterns in their lungs because the immune system response blew holes in alveoli, which then merged together as they healed.
A recent study on the novel coronavirus found that 14% of patients ended up with this honeycomb pattern as well. (They call it "ground glass opacity".) https://www.thelancet.com/journals/lancet/article/PIIS0140-6...