I agree with taking it to someone that knows how to do it, but if you do want to try it yourself, do not use a dremel!!
Use some fine grit emery wrapped around a pencil, or a piece of dowel rod about the size of a pencil & do it manually. Polish in the direction that the round travels. Be sure to maintain the same ramp angle. Just a few strokes will highlight the rough spot. Then, rake your finger nail across it to see if you can feel it. I have a pistol with visable scratch marks across the ramp. I took it to a LGS & let their 1911 guru check it. He couldn't feel it, even though it was easily visable & he said don't worry about it.