Not sure what kind of boat your running, but I had a dent in my keel on my previous Lund and I ran that boat hard for 4 years without any problems at all. I cannot speak on the side of a professional on this topic, just experience.
Same here on not a professional but I have a riveted Jon boat and a bad dent and I use it. On my off time I did some welding on it just to reasure me. You could do that to but I would just run it.