It's deserved, Tonums!! You're an incredible artist as well as a shmexy pirate ninja! (Though if you don't start putting apostraphes in 'you're' I really will kick you in the moolies. But with love, of course.)
Another way you can get rid of the line is before you flatten the pieces as one in Ps: overlap your scans, make the top scan 50% transparent so you can match the two up, go back to 100% solid on top scan before using either a 60, 100, 200 eraser size to slide across the line; then flatten. The eraser is dependent on how large your working pieces are.