I've never used nitro block so I've no idea how this will work. Can you put some mental bright neon colour behind your design and then re apply new nitro block to that as described above ?
In the custom world of automotive paint there used to be stuff called 'Vereble' ( which I can't remember how to spell proper like ) anyway, you'd use a 2 coat system, slow base and fast topcoat and it would crack with great effect if you used the right colours.
Just a thought to salvage your design. You might be surprised that people actually like it, random often gives designs an edge
