TrooperTim came over today to help me, and got the ridge completely sanded down. It can't be felt at all now, although the discoloration is still present. He also tried polishing out the sanding marks, but they wouldn't polish out. So we're going to prime and paint it, once I find out which color of white will work best on it.
Starting to feel like this is all going to be ok!
I'll post the pics, if anyone can't tell where the line is, let me know and I'll add arrows. It looks a LOT better, and feels smooth.
Thank you, TrooperTim.