Open sores might make them more prone to infection but they can heal up quite well given time. At my dad's old pond we had a 14-1/2" LMB that got hit hard with a boat prop one year, it sliced a 1" X 3" chunk of skin off it's side. I caught that fish at least five times while it was healing up, it was skinny and looked horrible for several months and I was very tempted to put it out of it's misery. The following year I caught that same fish one more time and it was super healthy, all it had left was 1 centimeter x 1 centimeter scar on it's side and it had grown to 16".
