Is this one of Kurts tutes???
I would delete the 3rd set along toward the back then space out the geometry on the head again just to let it breath. Then you wont affect the hand. You could delete the edge you have hilited down to the middle of the forearm then correct it by adding a bit of geo and spinning some faces until you have quads again. But I think for now stick with my first suggestion, then at least you can redirect any geo down the back of the model and join it up somewhere in the middle. But bear in mind you are making clothes for this so you could actually cut the arm off and hide the rest with the clothing if you wanted