As Wulf stated, use a polishing stick to lightly take down the ridge.
You probably concentrated too much on making sure the demarkation line was covered, in this case too well. I hit then masking line first lightly then concentrate on the rest of the area, returning to the line as I finish.
The one mistake I see modelers make is when trying to get a faded or worn finish on the paint scheme they tend to apply less in the center of the colored area yet get it on too heavy around the borders. This gives the appearance that the paint doesn't fade where it meets another color. But in reality it fades the same.
Learning to get that uniform look takes practice and good technique. It is better to do it in several light coats versus one heavy one. Always take the model into a different source of light to see what it looks like. Painting under flourescent lights will cast a different look than if it is viewed under sunlight or incadescent light. I'll sometimes cast a flashlight beam onto the model to see what my results are.