Refurbish or tighten a neoprene neck seal?

My drysuit has been a dampsuit lately because the neoprene neck seal is leaking. I have tried to be very careful about tucking the seal in, have tried folding it in more, folding it in less, but I'll still end up with a shot of cold water down my neck. (Or 2, or 3...) I bought the suit used, and I think the seal is just worn out now.

So--another diver suggested tightening the seal by cutting out a wedge and gluing the edges together. If the cut was reinforced with seam tape opposite the skin side it seems like it might work... Has anyone done this? I couldn't find any info in the forums.