If your positive the sag is in the clearcoat, you should be able to remove it. I've heard of painters taking a razor blade "round" the corners first and try to scrape the heavy part of the sag off. Another trick I've heard of is taking a fine "file" and cutting it down so you have a piece about 1" long. "Dull" any sharp edges and then rub it along the sag. Then using a "hard" sanding block with #2000 grit you can level it out. Probably you could find a local painter willing to share some trade secrets with you, give'm a call. Just take it slow and easy, good luck.