Nothing to worry about, but you do need to address it
since it is lead, the corrosion aspect from steel or iron is less of an issue. Still, you will need to to seal it to prevent further migration.
Last fall when I hauled my boat, I went around and fully inspected the keel for any dings or delams that may have occurred during the season from hitting any junk. Everything looked great except in one area on the leading edge there was a very thin crack in the paint that when I pushed on it, it spit a little water. I carefully chipped off the paint that wasn't well bonded around the crack until I got to a solid bond.
I let the thing air out over the winter. I roughed up the area around the edge and the exposed lead and painted on some very thin epoxy and allow it to wick into the edges between the well adhered paint and the lead keel. I also painted the bare, roughed up lead. I let the epoxy set over night and then mixed up some filled epoxy (thick peanut butter consistency) and spread it onto the area where the paint was missing. I smoothed it out so that the contour matched the existing keel edge and adhered paint.
I let the filled epoxy cure for a couple of days and then sanded smooth and flush with the existing keel area with 120 and 180 grit paper. Then I just painted it with bottom paint.
Will see how it works out.