Spark plug wire issues

I bought a set of Bosch spark plug wires (17MM) and found that one of them would not go on the spark plug (it's the wire because I checked it on another plug). I went back to the store and got a new plug wire, and didn't realize til I got home that it was an 18MM. I am curious if it would cause any problems if I ran it. My other choice is to take off all the new wires, put my old ones back on, take them back to the store and get new wires and put those on. Thanks!!

return them and call summit or jegs.
While your at it Accel makes a nice coil for our rig.