Ah, good effort then Tom!
Personally I wouldn't try to conceal it by building up more layers of touch-up paint - in my experience this only leads to a messy rough edging after a couple of coats. (Even recently made this mistake with some tricky wing leading and trailing edges)
Better to take it as a learning curve and leave it as is, or maybe trim one edge of the bulge with a craft knife, wet the decal, and carefully try to remove the lower layer of the 'double up' by trimming, or just smoothing it over the adjacent decal strip (if that makes sense)
Evan